Recent advances in neuroradiology have enabled us to approach cavernous angioma in the brain stem. A case of large cavernous angioma, which was located in the pontomedullary junction, was removed surgically. A 24-year-old female was admitted with occipitalgia, dizziness, nausea, gait disturbance. On neurologic examination, the patient had right hemiparesis, slight right facial palsy and paresthesia, right hemiparesthesia, dysphagia. T1 weighted Gd enhanced MRI revealed a mixed intensity lesion. These findings were thought to be consistent with a cavernous angioma. Follow up MRI findings demonstrated progressive increase in cavernous angioma. Vertebral angiograms showed a mass sign and a venous angioma in the midline of the pontomedullary junction. Therefore, the operation was performed in an attempt to remove the cavernous angioma through the midline of the fouth ventricle. The operation was performed under monitoring of electromyogram of facial muscle and external ocular muscle. The cavernous angioma was removed totally, and addition neurogical deficits were minimal.