A tread (12) of a tire (10) has a two-layer structure. The tread (12) includes a base layer (23) provided on an inside in a radial direction and a cap layer (24) provided on an outside in the radial direction. The outer peripheral surface of the cap layer (24) constitutes a tread surface (17). The tread surface (17) is provided with a groove (18). A plurality of circular land portions (21) is formed by the adjacent grooves (18). The base layer (23) is provided with a convex portion (26) extended in a circumferential direction. A plurality of convex portions (26) is arranged in an axial direction. A height (h1) of the convex portion (26) is set to be 15% to 50% of a depth (d1) of the groove (18). A position (a dimension .DELTA.h) of a base bottom portion (29) of the base layer (23) based on an inner bottom portion (28) of the groove (18) is set at 1.6 mm or less from the inner bottom portion (28) of the groove (18).