This report focuses on the use of a diode laser on a 37-year-old woman with a glomus tympanicum tumor that completely filled her middle ear space. Through a postauricular approach, the exposed vascular tumor was gently coagulated to shrink it and sectioned to detach it from the middle ear using a diode laser, followed by the piecemeal removal of the tumor in toto. Ossicular reconstruction was performed in a single-stage tympano-ossiculoplasty. The patient had an uneventful postoperative course, and the audiometry revealed a complete closure of the air-bone gap one year after the operation. Due to its flexible delivery system that can sufficiently work in such restricted middle ear spaces, the application of the diode laser to treat the glomus tympanicum allowed adequate hemostasis to be achieved while avoiding subsequent sequelae. We demonstrate that the diode laser is a well applicable tool in treating highly vascular tumors of the middle ear like glomus tympanicum.