A case of polypoid endobronchial fibroma which led to subsegmental atelectasis in a 45-year-old male is reported. The diagnosis was made pre-operatively by roentgenographic examination, bronchoscopy and biopsy. A lobectomy of the right middle lobe was performed. The polypoid tumor occupied the lumen of the subsegmental bronchus of the right middle lobe and had a stalk. Histologically, the tumor was composed mostly of collagen bundles with scant spindle-shaped fibroblastic cells and a myxomatous component. There was neither cellular atypia nor mitotic figures nor infiltration of small round cells. The diagnosis was pulmonary fibroma of the endobronchial type. To date, 66 cases of pulmonary fibroma have been reported in the English literature since 1880; 21 of these were polypoid endobronchial fibroma. Only five cases of polypoid endobronchial fibroma including this case have been reported in the Japanese literature.