Calcifying fibrous tumors are extremely rare, benign tumors that are usually asymptomatic and found at regular health check. A 55-year-old woman was consulted by our department for an abnormal shadow in a chest X-ray. A CT scan showed a bumpy nodule on the diaphragm. Although it did not change in size in a year and appeared to be a benign tumor, it was impossible to make a definite diagnosis by imaging. Therefore we attempted to resect the lesion by surgical means. Tumors were disseminated on the right parietal and visceral pleura. Histological findings revealed spindle cells with psammoma bodies and calcification accompanied by lymphocyte and plasma cell infiltration. Immunohistochemical staining was positive only for vimentin. Because other soft tissue tumors such as inflammatory fibrous tumors, IgG4-related diseases, and solitary fibrous tumors were negative, we diagnosed this case as a calcifying fibrous tumor on the pleura. This is the 19th such case ever reported.