Middle ear adenoma is a rare disease that arises from the mucosa of the middle ear. Only a few cases of associated facial nerve paralysis have been reported. Facial nerve involvement is most likely related to nerve compression rather than tumor invasion of the nerve. We describe a case of a huge middle ear adenoma in a 63-year-old man. He presented with a 1-month history of right-sided otalgia, otorrhea, and facial palsy; he also had a 10-year history of right-sided hearing loss. A tympanomastoidectomy was performed. Intraoperatively, the tumor was found to fill the middle ear cavity as well as the entire diameter of the external auditory canal. The tumor had eroded the wall of the facial canal at the second genu, and it was tightly adherent to the epineurium. Focal inflammation around the tumor was observed at the exposed facial nerve. The tumor was removed and the facial nerve was decompressed. Immediately after surgery, the patient’s aural symptoms resolved. The final pathology evaluation established the diagnosis of a middle ear adenoma. At the 3-year follow-up, the ear cavity was completely healed and facial nerve function was improved.