Glomus tumors are known to be the most common tumor involving the middle ear cleft, however there has been no reported case in the Korean literature so far. Authors experienced a case of glomus tumor of the middle ear and mastoid in a 27 year old man with four years history of tinnitus. Clinical signs and symptoms were not characteristic of usual glomus tumor of the middle ear due to upward growth of this tumor, without showing any cranial nerve signs or inner ear findings. The lesion was a type D2 tumor with involvement of the petrous apex and the middle cranial fossa. This patient received 5600 rads of Co⁶⁰ irradiation, with slight reduction of size of the tumor, and on follow-up check for further neurosurgical and neurotological intervention.