A 61-year old man presented with a sudden onset of breathlessness. The total left pneumothorax was overlooked on the initial chest radiograph. One month later, the patient had a partial pneumothorax less than 20% on the radiograph, although he did not receive any therapy against pneumothorax, such as oxygen inhalation or needle aspiration. After the observation for one month, the lungs totally expanded. Pulmonary function tests demonstrated severe chronic obstructive pulmonary disease. To our knowledge, this is the first case in which the total secondary pneumothorax showed a spontaneous remission.