Pneumatic tire

A pneumatic tire including, on a tread surface of a tread portion, at least four rib-like land portions extending in a tire circumferential direction formed by at least three circumferential main grooves extending along the tire circumferential direction, and subsidiary grooves provided at intervals in the tire circumferential direction and connecting to each of the circumferential main grooves, forming block-like land portions at least in the rib-like land portions between the circumferential main groove closest to a tire equator line and the circumferential main groove located adjacent to said circumferential main groove, wherein

• a groove width of the subsidiary grooves changes midway, a relationship between a groove width (W1) of a first opening of the subsidiary groove with respect to the circumferential main groove on an outer side in a tire width direction and a groove width (W2) of a second opening of the subsidiary groove with respect to the circumferential main groove on an inner side in the tire width direction satisfies a range of 0.30≦W1/W2 ≦0.70, a relationship between a groove length (L1) on the tread surface having a region of the groove width (W1) and a groove length (L2) on the tread surface having a region of the groove width (W2) satisfies a range of 0.25≦L2/L1 ≦0.65, and sipes are provided on the tread surface of the block-like land portions, respective end portions of the sipes connecting to a position where the groove width (W1) of the subsidiary groove changes to the groove width (W2), and to a portion in a section of the subsidiary groove having the groove width (W1) between the subsidiary grooves located adjacent to each other in the tire circumferential direction;
• and
• a relationship between a groove depth (G1) of the circumferential main groove closest to the tire equator line and a groove depth (D1) in the section of the subsidiary groove having the groove width (W1) satisfies a range of 0.30≦D1/G1 ≦0.70, and a relationship between the groove depth (G1) of the circumferential main groove closest to the tire equator line and a groove depth (D2) in a section of the subsidiary groove having the groove width (W2) satisfies a range of 0.50≦D2/G1 ≦0.70, and wherein D2>D1.