The contents of the retropharyngeal space are limited to fat and retropharyngeal nodes. Primary tumors originating from the retropharyngeal space are rare. More than 25% of schwannomas are found in the head and neck region, and they are rarely found in the retropharyngeal space. Here, we report the case of a 44-year-old woman with a schwannoma confined to the left retropharyngeal space, who presented with snoring and a mild lump in the throat sensation. Physical examination revealed anterior bulging of the left oropharyngeal wall, with intact mucosa. Magnetic resonance imaging showed a well-defined, encapsulated tumor in the left retropharyngeal space with bright signal intensity on T2-weighted images and low signal intensity on T1-weighted images, which was strongly enhanced after gadolinium administration. The tumor was removed through a transoral approach, resulting in a short postoperative recovery time without complications. The pathologic diagnosis was schwannoma. The patient has been well and free of tumor recurrence for 2 years. From anatomic and physiologic viewpoints, excision through a transoral approach is a good choice for a confined retropharyngeal schwannoma.