Coronary artery dissection and intramural hematoma after blunt chest trauma are rare, but life-threatening, complications. Coronary intramural hematoma extension is even rarer. A 31-year-old man was transferred to our hospital for worsening left chest pain during while he was admitted at a nearby hospital due to blunt chest trauma. Bedside echocardiography showed akinesis of the left ventricular apex and anterior wall as well as hypokinesis of the mid-to-basal anteroseptal wall and mid-to-basal lateral and posterior walls of the left ventricle. Computed tomography coronary angiography revealed intramural hematoma in the left main (LM) coronary and proximal left anterior descending (LAD) arteries. Percutaneous coronary intervention, with bare metal stent implantation from the LM coronary artery to the proximal LAD artery, was performed to treat the occlusion caused by the hematoma. After stenting, the hematoma that compressed the LM coronary artery shifted the left circumflex (LCX) artery, and the intramural hematoma developed and extended to the LCX artery. To resolve this occlusion, a drug-eluting stent was successfully implanted in the LCX artery. The patient was discharged without complications. At 2-month follow-up, he remained asymptomatic, with no recurrence of cardiovascular symptoms. Delayed chest pain after trauma should be suspected during coronary dissection, and on treatment, care must be taken to extend the hematoma.