A 66-year-old man. He had myocardial infarction due to occlusion of the left anterior descending branch, which was subsequently complicated by ventricular septal perforation. Ventricular septal perforation was repaired through right ventricle incision, applying double patches for closure, and injecting glue between the patches. The early postoperative course was good, but the infarcted left ventricular anterior wall remained because of the right ventriculotomy approach. A left ventricular aneurysm was demonstrated on postoperative follow-up echocardiography, which gradually enlarged to become giant. Since symptoms of heart failure such as respiratory distress appeared, left ventriculoplasty was performed 29 months after the perforation of the initial surgery. Since thinned left ventricular wall remains following right ventriculotomy approach, risk of postoperative left ventricular aneurysm should be taken into account.