A 65-year-old woman was referred to our hospital for investigation of increased opacity in the right lower lung field of the chest X-ray. Chest CT demonstrated a large tumor in the right thoracic cavity. A preoperative needle biopsy was performed. The microscopic appearance revealed many spindle cells. An immunohistochemical study was positive for CD34 and vimentin. Solitary fibrous tumor of the pleura was strongly suspected and the operation was performed. The tumor arose from the visceral pleura and was pedunculated. The resected specimen was positive for CD34 and vimentin. The tumor was diagnosed as solitary fibrous tumor of the pleura. Although this case was diagnosed 11 years after detection, the tumor was completely resected. Solitary fibrous tumors are usually cured with complete resection, but long-term clinical follow up is needed because of the possibility of recurrence and metastasis.