diff --git a/MainForm.cs b/MainForm.cs
index e247432..d2dddfc 100644
--- a/MainForm.cs
+++ b/MainForm.cs
@@ -31,6 +31,7 @@
         private PictureBox _aperturePicture;
         private Label _apertureCurrentValue;
         private Label _apertureDifferenceValue;
+        private Label _apertureInstructionLabel;
 
         private ToolStripStatusLabel _cameraStatusLabel;
         private ToolStripStatusLabel _cameraInfoLabel;
@@ -175,13 +176,13 @@
             AddCaption(panel, "差（現在値 − 目標値）");
             _apertureDifferenceValue = AddValueLabel(panel, "--");
 
-            AddCaption(panel, "ROI位置微調整");
+            //AddCaption(panel, "ROI位置微調整");
+            _apertureInstructionLabel = AddInstruction(
+                panel,
+                BuildApertureInstructionText(AppSettings.ApertureCalculationRoi));
+
             panel.Controls.Add(CreateApertureRoiMovePanel());
 
-            AddInstruction(
-                panel,
-                "現在値が目標値（±1.0）となるように\r\nレンズの開口を調整してください。\r\n\r\n" +
-                $"赤枠: 計算ROI 128×128\r\n表示ROI: (860, 625), 1280×960\r\nROI移動: {AppSettings.ApertureRoiMoveStep}px単位");
             AddInstructionImage(panel, "LensApature.jpg");
 
             page.Controls.Add(split);
@@ -308,9 +309,9 @@
             return label;
         }
 
-        private static void AddInstruction(Control parent, string text)
+        private static Label AddInstruction(Control parent, string text)
         {
-            parent.Controls.Add(new Label
+            var label = new Label
             {
                 Text = text,
                 AutoSize = false,
@@ -319,7 +320,26 @@
                 Font = new Font("Yu Gothic UI", 12F),
                 TextAlign = ContentAlignment.MiddleLeft,
                 Padding = new Padding(8)
-            });
+            };
+            parent.Controls.Add(label);
+            return label;
+        }
+
+        private static string BuildApertureInstructionText(Rectangle calculationRoi)
+        {
+            return "現在値が目標値（±1.0）となるように\r\nレンズの開口を調整してください。\r\n\r\n" +
+                "ROI位置微調整\r\n" +
+                $"赤枠: ROI ({calculationRoi.X}, {calculationRoi.Y}), {calculationRoi.Width}×{calculationRoi.Height}\r\n" +
+                //$"表示ROI: ({AppSettings.ApertureDisplayRoi.X}, {AppSettings.ApertureDisplayRoi.Y}), {AppSettings.ApertureDisplayRoi.Width}×{AppSettings.ApertureDisplayRoi.Height}\r\n" +
+                $"ROI移動: {AppSettings.ApertureRoiMoveStep}px単位";
+        }
+
+        private void UpdateApertureInstructionText(Rectangle calculationRoi)
+        {
+            if (_apertureInstructionLabel != null)
+            {
+                _apertureInstructionLabel.Text = BuildApertureInstructionText(calculationRoi);
+            }
         }
 
         private static void AddInstructionImage(Control parent, string fileName)
@@ -458,6 +478,7 @@
             var button = (Button)sender;
             var delta = (Point)button.Tag;
             Rectangle roi = _processor.MoveApertureCalculationRoi(delta.X, delta.Y);
+            UpdateApertureInstructionText(roi);
             SaveApertureRoi(roi);
             _logger.Info($"Aperture ROI moved to ({roi.X}, {roi.Y}).");
         }
@@ -469,6 +490,7 @@
                 return;
 
             Rectangle applied = _processor.SetApertureCalculationRoi(roi.Value);
+            UpdateApertureInstructionText(applied);
             _logger.Info($"Aperture ROI restored to ({applied.X}, {applied.Y}).");
         }