A blade cooling structure of a gas turbine, which can reduce the pressure loss of a cooling medium without decreasing the heat transfer coefficient, is provided. The blade cooling structure comprises a cooling passage (15) for flowing cooling air (A) from a proximal end portion (12) toward a blade portion (14) of a moving blade (11), a plurality of turbulators (21) arranged, on both wall surfaces of the cooling passage (15) opposing each other, in such a manner as to be inclined with respect to the flowing direction of the cooling air (A), and a plurality of dimples (22) formed in a downstream region (N) downstream of a center position (O) in the flowing direction of the cooling air (A) on the wall surface of the cooling passage (15) between the adjacent turbulators (21).