A motorcycle pneumatic tire comprising: a pair of bead portions; a pair of side wall portions continuously extending on the respective bead portions; a tread portion toroidally extending between the side wall portions; at least one carcass reinforcing the respective portions between the pair of the bead portions; and a designated rotation direction when mounted on a motorcycle, wherein the motorcycle pneumatic tire further comprises, on its ground-contact surface: a first inclined groove extending on a tire width-direction outer side from the vicinity of a tire equator and being inclined in the same direction as the tire rotation direction; and a short groove arranged on an extension of a tire width-direction outer end of the first inclined groove, a tread width TW is a tire width-direction distance between tread ends, which is measured along the ground-contact surface in a state where the tire is fitted to an application rim and inflated to a prescribed internal pressure with no load, wherein the "prescribed internal pressure" refers to an air pressure that corresponds to the maximum load capacity at the application size prescribed in the industrial standard, the tire width-direction outer end of the first inclined groove is positioned in the vicinity of a point at 1/4 of the tread width TW from the tire equator on the tire width-direction outer side, while a tire width-direction inner end of the short groove is positioned in a range of 1/4 to 5/16 of the tread width TW from the tire equator on the tire width-direction outer side, and an inclination angle of the first inclined groove with respect to a tire circumferential direction increases toward the tire width-direction outer side, and characterized in that an angle θ A formed by a groove wall of the tire width-direction outer end of the first inclined groove with respect to the direction perpendicular to the tire surface, and an angle θ B formed by a groove wall of the tire width-direction inner end of the short groove with respect to the direction perpendicular to the tire surface, satisfy a relationship of θ A > θ B. a pair of bead portions; a pair of side wall portions continuously extending on the respective bead portions; a tread portion toroidally extending between the side wall portions; at least one carcass reinforcing the respective portions between the pair of the bead portions; and a designated rotation direction when mounted on a motorcycle, wherein the motorcycle pneumatic tire further comprises, on its ground-contact surface: a first inclined groove extending on a tire width-direction outer side from the vicinity of a tire equator and being inclined in the same direction as the tire rotation direction; and a short groove arranged on an extension of a tire width-direction outer end of the first inclined groove, a tread width TW is a tire width-direction distance between tread ends, which is measured along the ground-contact surface in a state where the tire is fitted to an application rim and inflated to a prescribed internal pressure with no load, wherein the "prescribed internal pressure" refers to an air pressure that corresponds to the maximum load capacity at the application size prescribed in the industrial standard, the tire width-direction outer end of the first inclined groove is positioned in the vicinity of a point at 1/4 of the tread width TW from the tire equator on the tire width-direction outer side, while a tire width-direction inner end of the short groove is positioned in a range of 1/4 to 5/16 of the tread width TW from the tire equator on the tire width-direction outer side, and an inclination angle of the first inclined groove with respect to a tire circumferential direction increases toward the tire width-direction outer side, and characterized in that an angle θ A formed by a groove wall of the tire width-direction outer end of the first inclined groove with respect to the direction perpendicular to the tire surface, and an angle θ B formed by a groove wall of the tire width-direction inner end of the short groove with respect to the direction perpendicular to the tire surface, satisfy a relationship of θ A > θ B.