The amount of cooling air (cooling medium) can be reduced, and low-temperature cooling air is prevented from being blown out through film cooling holes. Part of a cooling medium impingement-cooling an inner circumferential surface (17) of a blade main body (11) located on a ventral side further impingement-cools the inner circumferential surface (17) of the blade main body (11) located on a dorsal side and is blown out through film cooling holes (13) in the blade main body (11) that are located on the dorsal side.
