We experienced differential lung ventilation using laryngeal mask airway (LMA) and a bronchial blocker tube for a patient with unanticipated difficult intubation. A 27-year-old man was diagnosed as the left spontaneous pneumothorax and scheduled for bulla excision with video-assisted thoracic surgery. Because of failure in tracheal intubation of the usual double lumen tube, we inserted LMAProseal #4 and accomplished differential lung ventilation using a bronchial blocker tube through LMA. This method will be effective in differential lung ventilation of the patient with difficult airway.