A turbine blade is provided that can reduce a total pressure loss at a blade cross-section on a tip side of the turbine rotor blade and suppress degradation in performance even if cooling air mixes in toward the rotor blade. The turbine rotor blade mounted to a rotor to form a turbine blade row rotating in a stationary member includes a platform forming a gas passage through which a mainstream gas flows and an airfoil extending from a gas passage plane in a radial direction vertical to the rotational axis of the rotor, the gas passage plane being a plane of the platform and forming the gas passage. A clearance between the tip-side end face which is a leading end-side end face of the airfoil and the stationary member facing the tip-side end face is defined so as to be smaller on the downstream side in the flow direction of the mainstream gas than on the upstream side.
