diff --git a/A00_Common/spreadsheet/spreadsheet_commands.ts b/A00_Common/spreadsheet/spreadsheet_commands.ts
index e89a56a8..2a98c605 100644
--- a/A00_Common/spreadsheet/spreadsheet_commands.ts
+++ b/A00_Common/spreadsheet/spreadsheet_commands.ts
@@ -450,7 +450,7 @@ function setAxis<V>(
   s: Sheet,
   axis: "행" | "열",
   idx: number[],
-  prop: "폭" | "높이" | "숨김",
+  prop: "폭" | "높이" | "숨김" | "묶음",
   value: V | null,
   undoOf: (idx: number[], prev: V | null) => Command,
 ): Command {
@@ -561,6 +561,19 @@ export function applyCommand(book: Workbook, command: Command): CommandEffect {
         })),
       );
     }
+    case "묶음설정": {
+      const s = sheetOf(book, command.시트);
+      const { 축 } = command;
+      return plain(
+        setAxis(s, 축, command.번호, "묶음", command.묶음, (번호, prev) => ({
+          종류: "묶음설정",
+          시트: s.id,
+          축,
+          번호,
+          묶음: prev,
+        })),
+      );
+    }
     case "틀고정": {
       const s = sheetOf(book, command.시트);
       const prev = { 행: s.틀고정?.행 ?? 0, 열: s.틀고정?.열 ?? 0 };
diff --git a/A00_Common/spreadsheet/spreadsheet_grid.css b/A00_Common/spreadsheet/spreadsheet_grid.css
index 9cf34e1d..be6845e2 100644
--- a/A00_Common/spreadsheet/spreadsheet_grid.css
+++ b/A00_Common/spreadsheet/spreadsheet_grid.css
@@ -116,6 +116,19 @@
   cursor: col-resize;
 }
 
+.aislo-grid__outline-btn {
+  position: absolute;
+  z-index: 2;
+  box-sizing: border-box;
+  padding: 0;
+  border: 1px solid var(--aislo-grid-head-border);
+  background: #fff;
+  color: var(--aislo-grid-head-fg);
+  font-size: 0.7em;
+  line-height: 1;
+  cursor: pointer;
+}
+
 .aislo-grid__resize--row {
   left: 0;
   bottom: -3px;
diff --git a/A00_Common/spreadsheet/spreadsheet_grid.ts b/A00_Common/spreadsheet/spreadsheet_grid.ts
index 9aec9cba..6f455663 100644
--- a/A00_Common/spreadsheet/spreadsheet_grid.ts
+++ b/A00_Common/spreadsheet/spreadsheet_grid.ts
@@ -12,7 +12,7 @@
 
 import "./spreadsheet_grid.css";
 import { toFrac } from "@ui/sheet/ui_template_sheet_frac";
-import { colIndex, parseA1, parseRange, toA1 } from "./spreadsheet_address";
+import { colIndex, colName, parseA1, parseRange, toA1 } from "./spreadsheet_address";
 import {
   applyCellStyle,
   cellStyleAt,
@@ -22,14 +22,17 @@ import {
 } from "./spreadsheet_cellstyle";
 import {
   buildColGeometry,
+  buildOutlineRuns,
   buildRowGeometry,
   commitColWidth,
   commitRowHeight,
+  isExplicitHidden,
   makeColHeaderCell,
   makeRowHeaderCell,
   startDragResize,
   visibleIndices,
   type LineGeometry,
+  type OutlineRun,
 } from "./spreadsheet_headers";
 import { formatValue } from "./spreadsheet_numfmt";
 import { MAX_COLS, MAX_ROWS } from "./spreadsheet_types";
@@ -51,6 +54,7 @@ import type {
 
 const HEAD_ROW_H_BASE = 24;
 const HEAD_COL_W_BASE = 46;
+const OUTLINE_GUTTER_BASE = 14;
 const RESIZE_HOTZONE = 4;
 const REF_COLORS = ["#1a73e8", "#e8710a", "#0f9d58", "#a142f4", "#d93025"];
 const ZOOM_MIN = 0.1;
@@ -232,8 +236,15 @@ export function createGrid(ctx: SpreadsheetContext): GridHandle {
   let frozenH = 0;
   let lastSheetId = "";
   let zoom = 1;
-  const headRowH = (): number => Math.round(HEAD_ROW_H_BASE * zoom);
-  const headColW = (): number => Math.round(HEAD_COL_W_BASE * zoom);
+  let rowOutlineRuns: OutlineRun[] = [];
+  let colOutlineRuns: OutlineRun[] = [];
+  /** 행 묶음 윤곽 띠 — 행 머리 왼쪽(있을 때만) · 열 묶음 띠는 열 머리 위. */
+  const rowGutterW = (): number =>
+    rowOutlineRuns.length ? Math.round(OUTLINE_GUTTER_BASE * zoom) : 0;
+  const colGutterH = (): number =>
+    colOutlineRuns.length ? Math.round(OUTLINE_GUTTER_BASE * zoom) : 0;
+  const headRowH = (): number => Math.round(HEAD_ROW_H_BASE * zoom) + colGutterH();
+  const headColW = (): number => Math.round(HEAD_COL_W_BASE * zoom) + rowGutterW();
 
   const resize = new ResizeObserver(() => layoutPanes());
   resize.observe(root);
@@ -381,18 +392,33 @@ export function createGrid(ctx: SpreadsheetContext): GridHandle {
     poolSweep(pool, keep);
   }
 
+  /** 건너뛴 자리(prev+1..cur-1) 안에 사용자 숨김 · 필터 걸러짐이 있나(묶음 접힘은 빼고 — 화면 표시가 다름). */
+  function colHiddenGap(sheet: Sheet, prev: number, cur: number): boolean {
+    for (let i = prev + 1; i < cur; i += 1)
+      if (isExplicitHidden(sheet.열?.[colName(i)])) return true;
+    return false;
+  }
+  function rowHiddenGap(sheet: Sheet, prev: number, cur: number): boolean {
+    for (let i = prev + 1; i < cur; i += 1)
+      if (isExplicitHidden(sheet.행?.[String(i + 1)])) return true;
+    return false;
+  }
+
   function layoutColHeaders(
     cols: number[],
     pool: CellPool,
     container: HTMLElement,
     base: number,
   ): void {
+    const sheet = ctx.sheet();
     const keep = new Set<string>();
+    const top = colGutterH();
+    const height = Math.round(HEAD_ROW_H_BASE * zoom);
     cols.forEach((c, i) => {
       const key = String(c);
       keep.add(key);
       const prev = i > 0 ? cols[i - 1] : c - 1;
-      const hiddenBefore = c - prev > 1;
+      const hiddenBefore = c - prev > 1 && colHiddenGap(sheet, prev, c);
       let cellEl = pool.used.get(key);
       if (!cellEl) {
         const built = makeColHeaderCell(c, 0, 0, hiddenBefore);
@@ -411,7 +437,9 @@ export function createGrid(ctx: SpreadsheetContext): GridHandle {
         });
       }
       cellEl.style.left = `${colGeo.offset(c) - base}px`;
+      cellEl.style.top = `${top}px`;
       cellEl.style.width = `${colGeo.size(c)}px`;
+      cellEl.style.height = `${height}px`;
       cellEl.classList.toggle("aislo-grid__colhead--hidden-before", hiddenBefore);
     });
     poolSweep(pool, keep);
@@ -423,12 +451,15 @@ export function createGrid(ctx: SpreadsheetContext): GridHandle {
     container: HTMLElement,
     base: number,
   ): void {
+    const sheet = ctx.sheet();
     const keep = new Set<string>();
+    const left = rowGutterW();
+    const width = Math.round(HEAD_COL_W_BASE * zoom);
     rows.forEach((r, i) => {
       const key = String(r);
       keep.add(key);
       const prev = i > 0 ? rows[i - 1] : r - 1;
-      const hiddenBefore = r - prev > 1;
+      const hiddenBefore = r - prev > 1 && rowHiddenGap(sheet, prev, r);
       let cellEl = pool.used.get(key);
       if (!cellEl) {
         const built = makeRowHeaderCell(r, 0, 0, hiddenBefore);
@@ -447,12 +478,79 @@ export function createGrid(ctx: SpreadsheetContext): GridHandle {
         });
       }
       cellEl.style.top = `${rowGeo.offset(r) - base}px`;
+      cellEl.style.left = `${left}px`;
       cellEl.style.height = `${rowGeo.size(r)}px`;
+      cellEl.style.width = `${width}px`;
       cellEl.classList.toggle("aislo-grid__rowhead--hidden-before", hiddenBefore);
     });
     poolSweep(pool, keep);
   }
 
+  /** 묶음 접힘 뒤집기(같은 묶음 자리 모두) → `묶음설정` dispatch. */
+  function outlineToggle(axis: "행" | "열", run: OutlineRun): void {
+    const idx: number[] = [];
+    for (let i = run.from; i <= run.to; i += 1) idx.push(i);
+    ctx.dispatch({
+      종류: "묶음설정",
+      시트: ctx.sheet().id,
+      축: axis,
+      번호: idx,
+      묶음: { 층: 1, 접힘: !run.collapsed },
+    });
+  }
+
+  /** 윤곽 +/- 단추 — 행 묶음 마지막 다음 자리(머리 왼쪽 띠) · 열 묶음도 같은 이치(머리 위 띠).
+   * 여러 층(중첩)은 1단계 다음(지금은 늘 층 1). */
+  function renderRowOutline(): void {
+    rowHeadInnerFrozen.querySelectorAll(".aislo-grid__outline-btn").forEach((n) => n.remove());
+    rowHeadInnerScroll.querySelectorAll(".aislo-grid__outline-btn").forEach((n) => n.remove());
+    if (!rowOutlineRuns.length) return;
+    const gw = rowGutterW();
+    for (const run of rowOutlineRuns) {
+      const btnRow = Math.min(run.to + 1, extent.rows - 1);
+      const container = btnRow < frozenRows ? rowHeadInnerFrozen : rowHeadInnerScroll;
+      const base = btnRow < frozenRows ? 0 : rowGeo.offset(frozenRows);
+      const btn = document.createElement("button");
+      btn.type = "button";
+      btn.className = "aislo-grid__outline-btn";
+      btn.textContent = run.collapsed ? "+" : "−";
+      btn.style.top = `${rowGeo.offset(btnRow) - base}px`;
+      btn.style.left = "0";
+      btn.style.width = `${gw}px`;
+      btn.style.height = `${rowGeo.size(btnRow) || Math.round(HEAD_ROW_H_BASE * zoom)}px`;
+      btn.addEventListener("click", (ev) => {
+        ev.stopPropagation();
+        outlineToggle("행", run);
+      });
+      container.append(btn);
+    }
+  }
+
+  function renderColOutline(): void {
+    colHeadInnerFrozen.querySelectorAll(".aislo-grid__outline-btn").forEach((n) => n.remove());
+    colHeadInnerScroll.querySelectorAll(".aislo-grid__outline-btn").forEach((n) => n.remove());
+    if (!colOutlineRuns.length) return;
+    const gh = colGutterH();
+    for (const run of colOutlineRuns) {
+      const btnCol = Math.min(run.to + 1, extent.cols - 1);
+      const container = btnCol < frozenCols ? colHeadInnerFrozen : colHeadInnerScroll;
+      const base = btnCol < frozenCols ? 0 : colGeo.offset(frozenCols);
+      const btn = document.createElement("button");
+      btn.type = "button";
+      btn.className = "aislo-grid__outline-btn";
+      btn.textContent = run.collapsed ? "+" : "−";
+      btn.style.left = `${colGeo.offset(btnCol) - base}px`;
+      btn.style.top = "0";
+      btn.style.width = `${colGeo.size(btnCol) || Math.round(HEAD_COL_W_BASE * zoom)}px`;
+      btn.style.height = `${gh}px`;
+      btn.addEventListener("click", (ev) => {
+        ev.stopPropagation();
+        outlineToggle("열", run);
+      });
+      container.append(btn);
+    }
+  }
+
   function renderVisible(): void {
     root.classList.toggle("aislo-grid--gridlines", gridlines());
     const w = root.clientWidth;
@@ -490,6 +588,8 @@ export function createGrid(ctx: SpreadsheetContext): GridHandle {
       rowHeadInnerScroll,
       rowGeo.offset(frozenRows),
     );
+    renderRowOutline();
+    renderColOutline();
 
     renderRowOfCells(frozenRowsVisible, frozenColsVisible, pools.tl, paneTLInner, 0, 0);
     renderRowOfCells(
@@ -528,6 +628,8 @@ export function createGrid(ctx: SpreadsheetContext): GridHandle {
     rowGeo = scaledGeometry(baseRowGeo, zoom);
     extent = computeExtent(sheet);
     merges = buildMergeMap(sheet);
+    rowOutlineRuns = buildOutlineRuns(sheet.행, (k) => Number(k) - 1);
+    colOutlineRuns = buildOutlineRuns(sheet.열, colIndex);
     frozenRows = Math.min(sheet.틀고정?.행 ?? 0, extent.rows);
     frozenCols = Math.min(sheet.틀고정?.열 ?? 0, extent.cols);
     spacer.style.width = "1px";
diff --git a/A00_Common/spreadsheet/spreadsheet_headers.ts b/A00_Common/spreadsheet/spreadsheet_headers.ts
index 3d8be157..50e4cc0b 100644
--- a/A00_Common/spreadsheet/spreadsheet_headers.ts
+++ b/A00_Common/spreadsheet/spreadsheet_headers.ts
@@ -105,7 +105,7 @@ export function buildColGeometry(book: Workbook, sheet: Sheet): LineGeometry {
   for (const [key, info] of Object.entries(sheet.열 ?? {})) {
     const c = colIndex(key);
     if (c < 0) continue;
-    if (info.숨김) overrides.set(c, 0);
+    if (info.숨김 || info.묶음?.접힘) overrides.set(c, 0);
     else if (info.폭 !== undefined) overrides.set(c, colCharsToPx(info.폭));
   }
   return new SparseGeometry(base, overrides);
@@ -117,12 +117,41 @@ export function buildRowGeometry(book: Workbook, sheet: Sheet): LineGeometry {
   for (const [key, info] of Object.entries(sheet.행 ?? {}) as [string, RowInfo][]) {
     const r = Number(key) - 1;
     if (!Number.isInteger(r) || r < 0) continue;
-    if (info.숨김) overrides.set(r, 0);
+    if (info.숨김 || info.걸러짐 || info.묶음?.접힘) overrides.set(r, 0);
     else if (info.높이 !== undefined) overrides.set(r, ptToPx(info.높이));
   }
   return new SparseGeometry(base, overrides);
 }
 
+/** 접힌 윤곽 묶음(연속 자리) — 묶음 있는 자리를 모아 붙은 것끼리 한 덩이로(같은 접힘 값끼리만). */
+export interface OutlineRun {
+  from: number;
+  to: number;
+  collapsed: boolean;
+}
+
+export function buildOutlineRuns<T extends { 묶음?: { 층: number; 접힘?: boolean } }>(
+  records: Record<string, T> | undefined,
+  indexOf: (key: string) => number,
+): OutlineRun[] {
+  const items = Object.entries(records ?? {})
+    .map(([key, info]) => ({ i: indexOf(key), collapsed: !!info.묶음?.접힘, has: !!info.묶음 }))
+    .filter((x) => x.has && x.i >= 0)
+    .sort((a, b) => a.i - b.i);
+  const runs: OutlineRun[] = [];
+  for (const it of items) {
+    const last = runs[runs.length - 1];
+    if (last && last.to === it.i - 1 && last.collapsed === it.collapsed) last.to = it.i;
+    else runs.push({ from: it.i, to: it.i, collapsed: it.collapsed });
+  }
+  return runs;
+}
+
+/** 그 자리가 숨김 · 걸러짐(사용자 · 필터) 인가 — 묶음 접힘은 빼고(화면 표시가 다름). */
+export function isExplicitHidden(info: { 숨김?: boolean; 걸러짐?: boolean } | undefined): boolean {
+  return !!info?.숨김 || !!info?.걸러짐;
+}
+
 /** `from..to` 안에서 숨기지 않은 자리만. */
 export function visibleIndices(geo: LineGeometry, from: number, to: number): number[] {
   const list: number[] = [];
diff --git a/A00_Common/spreadsheet/spreadsheet_types.ts b/A00_Common/spreadsheet/spreadsheet_types.ts
index b86ae188..e533464c 100644
--- a/A00_Common/spreadsheet/spreadsheet_types.ts
+++ b/A00_Common/spreadsheet/spreadsheet_types.ts
@@ -128,11 +128,18 @@ export interface CellStyle {
   형식?: string;
 }
 
+/** 묶음(윤곽) — 층 1 부터(중첩 단계) · 접힘 이면 격자가 숨김처럼 그림(숨김 · 걸러짐과는 화면 표시가 다름 — 윤곽 +/- 단추). */
+export interface Outline {
+  층: number;
+  접힘?: boolean;
+}
+
 export interface ColumnInfo {
   /** 엑셀 글자 폭 단위(기본 글꼴 숫자 폭 기준) — 화면이 px 로 바꿈. */
   폭?: number;
   숨김?: boolean;
   서식?: number;
+  묶음?: Outline;
 }
 
 export interface RowInfo {
@@ -142,6 +149,7 @@ export interface RowInfo {
   서식?: number;
   /** 자동 필터가 숨긴 행 — 사용자 `숨김` 과 따로(필터 풀면 보임) · 격자는 숨김처럼 그림. */
   걸러짐?: boolean;
+  묶음?: Outline;
 }
 
 /** 자동 필터 — `범위` 첫 행 = 머리(단추) · `조건` = 열 글자 → 보일 값(보이는 글 · 빈 칸은 ""). 조건 없는 열은 다 보임. */
@@ -394,6 +402,8 @@ export type Command =
   | { 종류: "정렬"; 시트: string; 범위: CellRange; 차례: number[] }
   /** 자동 필터 켜기 · 조건 바꾸기 · 끄기(null) — `걸러짐` = 숨길 행(`filterCommand` 가 값으로 셈) */
   | { 종류: "필터"; 시트: string; 필터: AutoFilter | null; 걸러짐: number[] }
+  /** 행 · 열 묶기(윤곽) · 접기 · 펴기 · 풀기(`묶음` null) — 격자 윤곽 +/- 단추가 씀 */
+  | { 종류: "묶음설정"; 시트: string; 축: "행" | "열"; 번호: number[]; 묶음: Outline | null }
   /** 여러 명령 = 되돌리기 한 번 */
   | { 종류: "묶음"; 명령: Command[] };
 
diff --git a/resources/tester/spreadsheet/spreadsheet_grid_test.ts b/resources/tester/spreadsheet/spreadsheet_grid_test.ts
index d732dea1..44c80247 100644
--- a/resources/tester/spreadsheet/spreadsheet_grid_test.ts
+++ b/resources/tester/spreadsheet/spreadsheet_grid_test.ts
@@ -39,8 +39,18 @@ const sheet: Sheet = {
   },
   comments: { H4: "메모 — ROUNDDOWN 끝수 확인" },
   병합: ["A1:H1", "B8:C9"],
-  열: { A: { 폭: 14 }, D: { 숨김: true } },
-  행: { "1": { 높이: 22 }, "5": { 숨김: true } },
+  열: {
+    A: { 폭: 14 },
+    D: { 숨김: true },
+    E: { 묶음: { 층: 1 } },
+    F: { 묶음: { 층: 1 } },
+  },
+  행: {
+    "1": { 높이: 22 },
+    "5": { 숨김: true },
+    "11": { 묶음: { 층: 1 } },
+    "12": { 묶음: { 층: 1 } },
+  },
   틀고정: { 행: 3, 열: 1 },
   보기: { 눈금선: true },
 };
@@ -129,6 +139,14 @@ const ctx: SpreadsheetContext = {
         ...sheet.행,
         [String(r0 + 1)]: { ...sheet.행?.[String(r0 + 1)], 높이: command.높이 ?? undefined },
       };
+    } else if (command.종류 === "묶음설정") {
+      const table = command.축 === "열" ? "열" : "행";
+      const next = { ...sheet[table] } as Record<string, { 묶음?: unknown }>;
+      for (const i of command.번호) {
+        const key = command.축 === "열" ? String.fromCharCode(65 + i) : String(i + 1);
+        next[key] = { ...next[key], 묶음: command.묶음 ?? undefined };
+      }
+      (sheet as unknown as Record<string, unknown>)[table] = next;
     }
     grid.render();
   },