Retrophayngeal hematomas frequently develop in patients who had cervical vertebra fracture. The hematoma develops in the space between buccopharyngeal fascia and prevertebral fascia. But it rarely causes severe airway obstruction. We recently treated a patient who had dyspnea and dysphagia due to a retropharyngeal hematoma without any significant trauma history. First, tracheostomy was performed to maintain the airway. Then, incision and drainage was done under suspension laryngoscope. This case shows the fact that a retropharyngeal hematoma can result in severe airway obstruction even after a minor trauma.