A turbine blade comprising: an air foil including a pressurized-surface-side blade wall which is concavely formed from a leading edge end to a trailing edge end and a suction-surface-side blade wall which is convexly formed from the leading edge end to the trailing edge end, wherein a region in the vicinity of the leading edge end is defined as a leading edge region and a region in the vicinity of the trailing edge end is defined as a trailing edge region, and a plurality of cooling flow passages (26,27) arranged within the air foil and through which a cooling medium can flow from the leading edge region to the trailing edge region; a top plate which forms the apex of the air foil, has a heat-resistant coating applied on the upper surface thereof, and includes a plurality of cooling holes (28a-c); and a squealer which protrudes radially outward from the blade from the top plate, and is formed so as to extend from the leading edge end along the suction-surface-side blade wall in a peripheral direction of the blade to the starting end of the trailing edge region at the side of the suction-surface-side blade wall, and wherein the height of the top plate of the trailing edge region including the thickness of the heat-resistant coating is lower than the height of the top surface of the squealer characterized in that the height of the top plate of the leading edge region is formed so as to be lower than the height of the top plate of the trailing edge region, and an inclined portion which has an upward gradient toward the trailing edge region from the leading edge region is formed. an air foil including a pressurized-surface-side blade wall which is concavely formed from a leading edge end to a trailing edge end and a suction-surface-side blade wall which is convexly formed from the leading edge end to the trailing edge end, wherein a region in the vicinity of the leading edge end is defined as a leading edge region and a region in the vicinity of the trailing edge end is defined as a trailing edge region, and a plurality of cooling flow passages (26,27) arranged within the air foil and through which a cooling medium can flow from the leading edge region to the trailing edge region; a pressurized-surface-side blade wall which is concavely formed from a leading edge end to a trailing edge end and a suction-surface-side blade wall which is convexly formed from the leading edge end to the trailing edge end, wherein a region in the vicinity of the leading edge end is defined as a leading edge region and a region in the vicinity of the trailing edge end is defined as a trailing edge region, and a plurality of cooling flow passages (26,27) arranged within the air foil and through which a cooling medium can flow from the leading edge region to the trailing edge region; a top plate which forms the apex of the air foil, has a heat-resistant coating applied on the upper surface thereof, and includes a plurality of cooling holes (28a-c); and a squealer which protrudes radially outward from the blade from the top plate, and is formed so as to extend from the leading edge end along the suction-surface-side blade wall in a peripheral direction of the blade to the starting end of the trailing edge region at the side of the suction-surface-side blade wall, and