Dermoid cyst is a benign congenital cyst which is composed of squamous epithelium and skin appendages. This tumor is uncommon among pediatric patients and its middle ear cavity involvement is extremely rare. An 11-month-old male visited to clinic with a history of recurrent acute otitis media. A whitish mass filling the middle ear cavity was identified from the otoscopic examination. TB-CT showed the soft tissue mass similar to congenital cholesteatoma. Mastoidectomy was performed and histologically the mass was confirmed as a dermoid cyst. Only a few cases of dermoid cysts in middle ear cavity were reported not only in Korea, but also including international cases. Although the timing of growth and its clinical manifestation differed, most cases presented pathologic pattern leading to surgical removal of the dermoid cyst. This paper provides the clinical and surgical courses of the case and a review of the literature.