A case of benign localized pleural mesothelioma is reported. The patient was a 30-year-old female with no complaint. The mesothelioma was detected by routine chest radiography. The chest radiogram on admission revealed a mass located in the right middle-lower lung field adjacent to the lateral chest wall. Physical and laboratory examinations did not show any abnormality. Ultrasonography demonstarated a homogeneous mass between the chest wall and the lung. CT examination revealed a soft tissue mass adjacent to the chest wall having an extrapulmonary sign. A percutaneous needle biopsy was done. These examinations suggested that the mass was a slow growing pleural tumor. The patient underwent tumorectomy with partial resection of the right lung. The tumor was solid and approximately 4cm in diameter and 1.5cm in thickness. It arose from the visceral pleura and was pendunculated. The histological diagnosis was of a benign localized fibrous mesothelioma of the pleura.