A tire comprising: a first circumferential groove; two second circumferential grooves adjacent to both sides of the first circumferential groove in a tire width direction; a plurality of lateral grooves opened to the first circumferential groove and the second circumferential groove; and a plurality of blocks on a tread portion partitioned by the first circumferential groove, the second circumferential groove, and the plurality of lateral grooves, an air flow in a direction opposite to a tire rotating direction being generated in the first circumferential groove and the two second circumferential grooves during running of a vehicle; wherein each block of the plurality of blocks has: a first wall surface formed from a position where the lateral groove on a downstream side of the air flow is opened to the first circumferential groove, toward an upstream side of the air flow; a second wall surface formed from a position where the lateral groove on the downstream side of the air flow is opened to the second circumferential groove, toward the upstream side of the air flow; and a block corner portion formed at a position where the lateral groove on the upstream side of the air flow is opened to the second circumferential groove; when the two blocks on the upstream side and the downstream side of the air flow adjacent in a tire circumferential direction are viewed, a virtual surface obtained by extending, on the downstream side of the air flow, the second wall surface of the block on the upstream side intersects with the block corner portion of the block on the downstream side or passes through a position in the second circumferential groove which is apart from the block corner portion in the tire width direction; a groove width of the first circumferential groove gradually increases toward the downstream side of the air flow at the first wall surface of the block; and the first wall surface of the block is a curved surface curved toward the inside of the lateral groove on the downstream side of the air flow. a first circumferential groove; two second circumferential grooves adjacent to both sides of the first circumferential groove in a tire width direction; a plurality of lateral grooves opened to the first circumferential groove and the second circumferential groove; and a plurality of blocks on a tread portion partitioned by the first circumferential groove, the second circumferential groove, and the plurality of lateral grooves, an air flow in a direction opposite to a tire rotating direction being generated in the first circumferential groove and the two second circumferential grooves during running of a vehicle; wherein each block of the plurality of blocks has: a first wall surface formed from a position where the lateral groove on a downstream side of the air flow is opened to the first circumferential groove, toward an upstream side of the air flow; a second wall surface formed from a position where the lateral groove on the downstream side of the air flow is opened to the second circumferential groove, toward the upstream side of the air flow; and a block corner portion formed at a position where the lateral groove on the upstream side of the air flow is opened to the second circumferential groove; a first wall surface formed from a position where the lateral groove on a downstream side of the air flow is opened to the first circumferential groove, toward an upstream side of the air flow; a second wall surface formed from a position where the lateral groove on the downstream side of the air flow is opened to the second circumferential groove, toward the upstream side of the air flow; and a block corner portion formed at a position where the lateral groove on the upstream side of the air flow is opened to the second circumferential groove; when the two blocks on the upstream side and the downstream side of the air flow adjacent in a tire circumferential direction are viewed, a virtual surface obtained by extending, on the downstream side of the air flow, the second wall surface of the block on the upstream side intersects with the block corner portion of the block on the downstream side or passes through a position in the second circumferential groove which is apart from the block corner portion in the tire width direction; a groove width of the first circumferential groove gradually increases toward the downstream side of the air flow at the first wall surface of the block; and the first wall surface of the block is a curved surface curved toward the inside of the lateral groove on the downstream side of the air flow.