Peripheral lung lipoma is extremity rare entity. To date 13 English literature and 5 Japanese cases including our case were published since Buchman's 1st report in 1911. A 53 year-old man was sent to our hospital with 2.5 cm lung mass detected on chest X-ray by annual health check. Computed tomography(CT)scan revealed homogenous fat density mass which was thought benign tumor, however, because of rapid growth lung mass which has not been detected on chest X-ray 1 year before, surgery was inevitable choice for diagnosis. On operative findings, lung adhesion and many vessels were seen around the mass. These facts suggested some possibility of the relationship between inflammation and the occurrence, growth of lipoma. We present a rare case of peripheral lung lipoma with rapid growth pattern.