diff --git a/server/api/src/main/java/com/hanwha/nexacrodemo/report/ReportService.java b/server/api/src/main/java/com/hanwha/nexacrodemo/report/ReportService.java
index ca3f2f1..0d1803b 100644
--- a/server/api/src/main/java/com/hanwha/nexacrodemo/report/ReportService.java
+++ b/server/api/src/main/java/com/hanwha/nexacrodemo/report/ReportService.java
@@ -169,11 +169,11 @@ public class ReportService {
         Row titleRow = sheet.createRow(0);
         titleRow.setHeightInPoints(28);
         createCell(titleRow, 0, "한화 연결 집계 요약", styles.get("title"));
-        sheet.addMergedRegion(new CellRangeAddress(0, 0, 0, 3));
+        mergeTitleRegion(sheet, 0, 4);
 
         Row subtitleRow = sheet.createRow(1);
         createCell(subtitleRow, 0, "회계기간 " + fiscalPeriod + " | 생성시각 " + generatedAt(), styles.get("subtitle"));
-        sheet.addMergedRegion(new CellRangeAddress(1, 1, 0, 3));
+        mergeTitleRegion(sheet, 1, 4);
 
         Row sectionRow = sheet.createRow(3);
         createCell(sectionRow, 0, "주요 지표", styles.get("section"));
@@ -210,11 +210,11 @@ public class ReportService {
         Row titleRow = sheet.createRow(0);
         titleRow.setHeightInPoints(24);
         createCell(titleRow, 0, sheetName, styles.get("title"));
-        mergeIfNeeded(sheet, 0, columnCount);
+        mergeTitleRegion(sheet, 0, columnCount);
 
         Row subtitleRow = sheet.createRow(1);
         createCell(subtitleRow, 0, "회계기간 " + fiscalPeriod + " | 건수 " + rows.size(), styles.get("subtitle"));
-        mergeIfNeeded(sheet, 1, columnCount);
+        mergeTitleRegion(sheet, 1, columnCount);
 
         if (rows.isEmpty()) {
             Row emptyRow = sheet.createRow(3);
@@ -356,10 +356,9 @@ public class ReportService {
         cell.setCellStyle(style);
     }
 
-    private void mergeIfNeeded(Sheet sheet, int rowIndex, int columnCount) {
-        if (columnCount > 1) {
-            sheet.addMergedRegion(new CellRangeAddress(rowIndex, rowIndex, 0, columnCount - 1));
-        }
+    private void mergeTitleRegion(Sheet sheet, int rowIndex, int columnCount) {
+        int lastColumn = Math.max(1, columnCount - 1);
+        sheet.addMergedRegion(new CellRangeAddress(rowIndex, rowIndex, 0, lastColumn));
     }
 
     private CellStyle styleForKey(Map<String, CellStyle> styles, String key) {