A 67-year-old man presented with a case of recurrent subdural hematomas (SDHs) from a pseudoaneurysm at the cortical artery after mild head trauma. He had undergone two episodes of burr hole trephination and evacuation of SDH in a 6-day interval. Review of previous imaging findings and additional cerebral angiography then identified a pseudoaneurysm arising from the precentral branch of the middle cerebral artery. Acute rebleeding suddenly occurred, and the leak point on the cortical artery was completely repaired with a single suture. SDH from pseudoaneurysm after mild head injury is very unusual. The high morbidity and mortality rates necessitate early detection, but the rarity of this type of injury makes detection difficult. If the clinical course is not easily explainable and is worse than the severity of trauma, repeated SDHs occur, or abnormal lesions and/or subarachnoid hemorrhage are identified, computed tomography or magnetic resonance imaging with contrast medium should be performed to identify the underlying cerebrovascular diseases and determine whether cerebral angiography is necessary.