A stent fracture combined with a coronary artery aneurysm is a rare event. As these events can lead to a harmful outcome, such as the development of myocardial ischemia by in-stent restenosis or thrombosis, repeated coronary intervention may be required. We report a case of a stent fracture combined with a coronary artery aneurysm. The fracture was thought to have developed by mechanical stress produced from a change of regional wall motion after an anteroseptal myocardial infarction. As detected by the use of intravascular ultrasound, neither in-stent restenosis nor a thrombus in the fractured stent was present. A cardiac magnetic resonance image showed that no viable myocardium in the anteroseptal wall was present. Therefore, the patient underwent medical treatment without intervention of the fractured stent.