In the related art pneumatic tires, various methods of improving expelling capability of water which is trapped between the road surface and a tread have been used to reduce hydroplaning. For example, a method in which a streamline-shaped recess, when seen from the plane of a tread surface, is formed on a groove wall of a main groove provided along the circumferential direction of the tire is known (for example, Patent Document 1). According to such a pneumatic tire, a turbulent flow of water which flows in the main groove can be controlled and water expelling capability is improved.