Tracheo-innominate artery fistula is a rare complication after tracheostomy, but sometimes presents with fatal bleeding. A 10-year-old girl presented with massive bleeding from a tracheostomy that she underwent for prolonged respiratory failure caused by sequelae of mumps encephalitis. Tracheo-innominate artery fistula, complicated by tracheostomy was diagnosed, and she was transferred to our institution. Under general anesthesia, she underwent transection of the innominate artery to exclude the tracheo-innominate artery fistula via median sternotomy. Her postoperative course was uneventful without recurrent bleeding or infection. Considering the risk of tracheo-innominate artery fistula, careful observation is necessary to prevent catastrophic bleeding in patients with mechanical respiratory support via tracheostomy.