In the field of otolaryngology, fat injection is mainly performed for glottic insufficiency. We encountered a patient of tracheoesophageal fistula with a voice prosthesis after total laryngectomy, in whom the fistula grew too wide. This condition was difficult to treat by conservative therapy. We performed fat injection around the tracheoesophageal fistula, achieving sufficient reduction in the size of to prevent leakage. This treatment allowed continuous use of the voice the prosthesis by the patient.