diff --git a/resources/tester/test_est_exchange.py b/resources/tester/test_est_exchange.py
index 70dc32d36..4d153e615 100644
--- a/resources/tester/test_est_exchange.py
+++ b/resources/tester/test_est_exchange.py
@@ -225,10 +225,10 @@ def test_excel_quantity_document_roundtrip_keeps_optional_original_fields():
         """(()=>{
       const p=EstNative.empty();p.quantitySheets=[{Code:'Q',Name:'sheet',options:{digits:2,roundMode:2},
         rows:[{LineData:'1 = \\x120\\x12',markers:['r1']}],
-        items:[{Code:'r1',Name:'item',Size:null,Unite:null,GN:null,LinkCode:null,Extra:'keep'}]}];
+        items:[{Code:'r1',Name:'item',Size:null,Unite:null,GN:null,LinkCode:'X',Extra:'keep'}]}];
       const tables={QDocuments:[{Code:'Q',Name:'sheet',digits:2,roundMode:2}],
         QLines:[{DocumentCode:'Q',Position:1,LineData:'1 = \\x120\\x12',Markers:'["r1"]'}],
-        QItems:[{DocumentCode:'Q',Position:1,Code:'r1',Name:'item',Size:null,Unite:null,GN:null,TargetCode:null,TargetKey:null}]};
+        QItems:[{DocumentCode:'Q',Position:1,Code:'r1',Name:'item',Size:null,Unite:null,GN:null,TargetCode:'X',TargetKey:null}]};
       return {before:p.quantitySheets,after:EstExchange.apply(p,tables).quantitySheets};
     })()""",
     )
diff --git a/tools/est-test/native-exchange.js b/tools/est-test/native-exchange.js
index ea1638b68..e0e5a665f 100644
--- a/tools/est-test/native-exchange.js
+++ b/tools/est-test/native-exchange.js
@@ -193,8 +193,14 @@ const EstExchange = (() => {
             throw Error("수량 항목 수치 오류");
           next.GN = row.GN;
         } else if (!previous || previous.GN != null) next.GN = 0;
-        if (row.TargetCode != null) next.TargetCode = row.TargetCode;
-        else if (previous && (previous.TargetCode ?? previous.LinkCode)) next.TargetCode = "";
+        if (row.TargetCode != null) {
+          if (
+            !previous ||
+            Object.hasOwn(previous, "TargetCode") ||
+            row.TargetCode !== previous.LinkCode
+          )
+            next.TargetCode = row.TargetCode;
+        } else if (previous && (previous.TargetCode ?? previous.LinkCode)) next.TargetCode = "";
         if (row.TargetKey != null) next.TargetKey = row.TargetKey;
         else if (previous?.TargetKey) next.TargetKey = "";
         return next;