Treatment choice for primary pulmonary sarcoma is complete surgical resection. A 69 year old man developed dyspnea due to left lung atelectasis. There was endobronchial tumor completely obstructing the left main bronchus. The tumor was resected completely by main bronchial resection via a left thoracotomy incision, and diagnosed as leiomyosarcoma. Bronchoscopy and computed tomography in 6 months after operation, there was no evidence of recurrence.