A pneumatic tire is disclosed, adapted to highly effectively combine on-ice and on-snow performances. The pneumatic tire includes block groups (G) formed by polygonal blocks (10), which are arranged closely in a tread portion (1). The polygonal blocks (10) are formed by grooves (9) including first groove (9a) with a groove width (W9a) between the polygonal blocks 10 neighboring with each other in the tire circumferential direction. The groove width (W9a) of the first grooves (9a) is larger than a groove width (W9b) of second grooves (9b) between the polygonal blocks 10 neighboring with each other with a zigzag pattern.