We report a case of cavernous sinus metastasis following postoperative maxillary gingival squamous cell carcinoma. An 83-year-old man was referred to our hospital due to pain in the left maxillary gingiva. Contrast-enhanced computed tomography imaging showed a mass lesion with bone destruction in the left maxillary gingiva. Biopsy indicated the presence of squamous cell carcinoma(T4bN1M0, Stage ⅣB), and the tumor was resected under general anesthesia. Four months after surgery, the patient experienced headache, and orbital pain, failing vision, and movement disorder of the left eye appeared. Magnetic resonance imaging revealed a tumor invading the cavernous sinus and orbit. The lesion was clinically diagnosed as metastatic cavernous sinus following postoperative left maxillary gingival carcinoma. Although the patient underwent chemotherapy, he died from multiple organ failure about 5 months after surgery.