A 59-year-old woman was referred to our hospital for chronic cough and myalgia. Polymyalgia rheumatica (PMR) and bronchial asthma were first diagnosed, and she was prescribed 15 mg/day prednisolone. PMR improved immediately. However, her chronic cough continued, and wheezing was heard on chest auscultation. The flow-volume loop showed a severe expiratory flow limitation and a notching sign at early expiration. Diffuse thickening and narrowing at the trachea and bilateral main bronchus were shown on chest CT. On flexible bronchoscope the trachea and bilateral main bronchus collapsed on expiration. We suspected relapsing polychondritis (RP), but she had no findings of saddle nose or deformity of the external ear. Therefore, biopsy of the tracheal cartilage was done. RP was diagnosed by the modified criteria of Damiani and the histology confirmed degeneration of the tracheal cartilage. She was treated by high dose corticosteroids, and her symptoms improved. This case report emphasizes the need to consider the possibility of RP as a cause of chronic cough or intractable asthma.