A pneumatic tire comprising: a tread portion defining a ground contacting width and provided with a plurality of circumferential rows of a plurality of blocks, said plurality of blocks defined by a plurality of main grooves extending continuously in the tire circumferential direction, a plurality of transverse grooves extending between the main grooves, and a plurality of transverse grooves extending between the main grooves and tread edges, said circumferential rows including at least one circumferential row (B2, B3) whose blocks include a plurality of bored blocks each provided in the top surface thereof with a blind hole for installing a stud, wherein said blind hole is disposed axially outward of a position spaced apart from the tire equator by an axial distance of at least 13 % of the ground contacting width (Tw), and every two circumferentially adjacent blind holes are shifted from each other in the tire axial direction, and said plurality of bored blocks including at least one bored block (5h1), whose blind hole is shifted towards the periphery of the bored block (5h1) and towards one of said plurality of main grooves, and which is provided with a reinforcing part for reinforcing the blind hole, wherein said reinforcing part protrudes into the main groove with decreasing the groove width of the main groove, characterized in that the reinforcing part is protrudingly formed so as to provide a wall thickness (t) of at least 5 mm for a wall surrounding the blind hole, with said plurality of blocks inclusive of the bored blocks having a geometrically same configuration excepting the protrudingly provided reinforcing part. a tread portion defining a ground contacting width and provided with a plurality of circumferential rows of a plurality of blocks, said plurality of blocks defined by a plurality of main grooves extending continuously in the tire circumferential direction, a plurality of transverse grooves extending between the main grooves, and a plurality of transverse grooves extending between the main grooves and tread edges, said circumferential rows including at least one circumferential row (B2, B3) whose blocks include a plurality of bored blocks each provided in the top surface thereof with a blind hole for installing a stud, wherein said blind hole is disposed axially outward of a position spaced apart from the tire equator by an axial distance of at least 13 % of the ground contacting width (Tw), and every two circumferentially adjacent blind holes are shifted from each other in the tire axial direction, and said plurality of bored blocks including at least one bored block (5h1), whose blind hole is shifted towards the periphery of the bored block (5h1) and towards one of said plurality of main grooves, and which is provided with a reinforcing part for reinforcing the blind hole, wherein said reinforcing part protrudes into the main groove with decreasing the groove width of the main groove, characterized in that the reinforcing part is protrudingly formed so as to provide a wall thickness (t) of at least 5 mm for a wall surrounding the blind hole, with said plurality of blocks inclusive of the bored blocks having a geometrically same configuration excepting the protrudingly provided reinforcing part.