Angiosarcoma of the scalp is a very rare disease. Secondary pneumothorax is known as a characteristic complication in this disease due to lung metastasis. In this study, 17 patients of angiosarcoma of the scalp, diagnosed at our hospital between 1996 and 2006, were analyzed. Secondary pneumothorax was observed in 10 of these patients, among which bilateral pneumothorax occurred in 5 relapse of pneumothorax occurred in 6 and pneumothorax with bloody pleural fluid occurred in 7 patients. Characteristic findings on chest CT were multiple thin-wall cavities and ground-glass attenuation around the cavity, located in bilateral subpleural lung fields. It is suggested that the subpleural thin-wall cavities cause pneumothorax. Although pleurosclerosis were performed in 5 patients and one of them had a subsequent partial resection of the lung, pneumothorax reocurred within a short period of time in all patients. The average survival time from the first pneumothorax episode was only 4.1 months. Secondary pneumothorax caused by this disease was intractable, resulting in an unfavorable outcome. It is necessary to develop a proper treatment strategy for secondary pneumothorax to create a favorable prognosis in this disease.