Traumatic intracranial aneurysms (TICAs) are rare and are associated with high rates of morbidity and mortality. TICAs usually result from head injuries caused by traffic accidents, industrial accidents, or gunshots. We report a traumatic aneurysm of the callosomarginal artery-cortical artery junction arising from a penetrating injury by scissors. A 51-year-old woman was admitted to our hospital after suffering a penetrating injury caused by scissors. Computed tomography (CT) and CT-angiography demonstrated a right orbital roof fracture, subarachnoid hemorrhage, frontal lobe hemorrhage, intraventricular hemorrhage, and a traumatic aneurysm of the right callosomarginal artery-cortical artery junction. We trapped the traumatic aneurysm and repositioned a galeal flap. Postoperative CT showed a small infarction in the left frontal lobe. Follow-up angiography two months later showed no residual aneurysm. We suggest that an aggressive surgical intervention be performed whenever TICA is diagnosed.