An internal carotid artery (ICA) tear during or after trans-sphenoidal surgery (TSS) is rare but may cause potentially lethal complications. A 23-year-old female patient visited our hospital for treatment of a Rathke's cleft cyst. The patient had massive hemorrhage during surgery and angiography performed after surgery showed laceration of the cavernous ICA. We successfully controlled the hemorrhage with emergency placement of an endovascular stent-graft.