The invention provides a gas turbine blade that is capable of reducing the temperature difference between the pressure side and the suction side even if the trailing-edge cooling channel is narrow, thereby lessening thermal stress as well.A gas turbine blade 1 comprises: an internal trailing-edge cooling channel formed by a suction-side cooling target surface 6a and a pressure-side cooling target surface 6b that face each other; and multiple vortex-generator-shaped fins 10 disposed between the two cooling target surfaces 6a and 6b such that the fins 10 connect the two cooling target surfaces 6a and 6b. Each of the vortex-generator-shaped fins 10 includes an oblique surface 33 located on the downstream side of the flow direction of a cooling medium. A normal line 34 to the oblique surface 33 intersects with one of the two cooling target surfaces 6a and 6b.