diff --git a/frontend/src/components/dataGridRowClipboard.test.ts b/frontend/src/components/dataGridRowClipboard.test.ts
new file mode 100644
index 0000000..232f4ff
--- /dev/null
+++ b/frontend/src/components/dataGridRowClipboard.test.ts
@@ -0,0 +1,41 @@
+import { describe, expect, it } from 'vitest';
+
+import { buildCopiedRowsForPaste, buildPastedRowsFromCopiedRows } from './dataGridRowClipboard';
+
+const rowKeyField = '__gonavi_row_key__';
+
+describe('dataGridRowClipboard', () => {
+  it('copies selected rows in selection order without the internal row key', () => {
+    const copiedRows = buildCopiedRowsForPaste({
+      rows: [
+        { [rowKeyField]: 'row-1', id: 1, name: 'alpha', hidden_note: 'A' },
+        { [rowKeyField]: 'row-2', id: 2, name: 'beta', hidden_note: 'B' },
+      ],
+      selectedRowKeys: ['row-2', 'row-1'],
+      columnNames: ['id', 'name', 'hidden_note'],
+      rowKeyField,
+    });
+
+    expect(copiedRows).toEqual([
+      { id: 2, name: 'beta', hidden_note: 'B' },
+      { id: 1, name: 'alpha', hidden_note: 'A' },
+    ]);
+  });
+
+  it('builds pasted rows as new rows with fresh internal keys', () => {
+    const pastedRows = buildPastedRowsFromCopiedRows({
+      rows: [
+        { id: 2, name: 'beta' },
+        { id: 1, name: 'alpha' },
+      ],
+      columnNames: ['id', 'name'],
+      rowKeyField,
+      createRowKey: (index) => `paste-${index}`,
+    });
+
+    expect(pastedRows).toEqual([
+      { [rowKeyField]: 'paste-0', id: 2, name: 'beta' },
+      { [rowKeyField]: 'paste-1', id: 1, name: 'alpha' },
+    ]);
+  });
+});
diff --git a/frontend/src/components/dataGridRowClipboard.ts b/frontend/src/components/dataGridRowClipboard.ts
new file mode 100644
index 0000000..e3688ea
--- /dev/null
+++ b/frontend/src/components/dataGridRowClipboard.ts
@@ -0,0 +1,66 @@
+export interface BuildCopiedRowsForPasteInput {
+  rows: Array<Record<string, any>>;
+  selectedRowKeys: any[];
+  columnNames: string[];
+  rowKeyField: string;
+  rowKeyToString?: (key: any) => string;
+}
+
+export interface BuildPastedRowsFromCopiedRowsInput {
+  rows: Array<Record<string, any>>;
+  columnNames: string[];
+  rowKeyField: string;
+  createRowKey: (index: number) => string;
+}
+
+const defaultRowKeyToString = (key: any): string => String(key);
+
+const getCopyableColumnNames = (columnNames: string[], rowKeyField: string): string[] =>
+  columnNames.filter((columnName) => columnName !== rowKeyField);
+
+const pickCopyableRowValues = (
+  row: Record<string, any>,
+  columnNames: string[],
+  rowKeyField: string,
+): Record<string, any> => {
+  const next: Record<string, any> = {};
+  getCopyableColumnNames(columnNames, rowKeyField).forEach((columnName) => {
+    next[columnName] = row?.[columnName];
+  });
+  return next;
+};
+
+export const buildCopiedRowsForPaste = ({
+  rows,
+  selectedRowKeys,
+  columnNames,
+  rowKeyField,
+  rowKeyToString = defaultRowKeyToString,
+}: BuildCopiedRowsForPasteInput): Array<Record<string, any>> => {
+  if (!Array.isArray(rows) || !Array.isArray(selectedRowKeys) || selectedRowKeys.length === 0) {
+    return [];
+  }
+
+  const rowsByKey = new Map<string, Record<string, any>>();
+  rows.forEach((row) => {
+    const rowKey = row?.[rowKeyField];
+    if (rowKey === undefined || rowKey === null) return;
+    rowsByKey.set(rowKeyToString(rowKey), row);
+  });
+
+  return selectedRowKeys
+    .map((selectedKey) => rowsByKey.get(rowKeyToString(selectedKey)))
+    .filter((row): row is Record<string, any> => Boolean(row))
+    .map((row) => pickCopyableRowValues(row, columnNames, rowKeyField));
+};
+
+export const buildPastedRowsFromCopiedRows = ({
+  rows,
+  columnNames,
+  rowKeyField,
+  createRowKey,
+}: BuildPastedRowsFromCopiedRowsInput): Array<Record<string, any>> =>
+  rows.map((row, index) => ({
+    [rowKeyField]: createRowKey(index),
+    ...pickCopyableRowValues(row, columnNames, rowKeyField),
+  }));