A tire for a motorcycle for running on rough terrain, comprising a tread portion having a designated rotation direction of the tire, wherein the tread portion includes a base surface and a plurality of blocks raised outward in a tire radial direction from the base surface, at least one of the plurality of blocks includes a finned block, the finned block includes a block main body and at least two fin portions having a smaller width in a tire axial direction than the block main body and extending to one side in a tire circumferential direction, a projection is provided between two fin portions of said at least two fin portions on the base surface, the projection is disposed within a block adjacent region which includes a gap portion between the two fin portions and an extension portion extending from the gap portion toward a heel side in the designated rotation direction so as to be parallel to the tire circumferential direction, the blocks include a crown block on a tire equator side and a middle block adjacent to the crown block in the tire axial direction, and characterized in that each of the crown block and the middle block is formed as the finned block, wherein the crown block includes three fin portions including a first fin portion on one side in the tire axial direction, a second fin portion on the other side in the tire axial direction, and a third fin portion between the first fin portion and the second fin portion, and wherein the middle block includes the two fin portions including a first fin portion on one side in the tire axial direction and a second fin portion on the other side in the tire axial direction, one projection is disposed in each of the block adjacent region between the first fin portion and the third fin portion and the block adjacent region between the second fin portion and the third fin portion of the crown block, and one projection is disposed in the block adjacent region between the first fin portion and the second fin portion of the middle block. the tread portion includes a base surface and a plurality of blocks raised outward in a tire radial direction from the base surface, at least one of the plurality of blocks includes a finned block, the finned block includes a block main body and at least two fin portions having a smaller width in a tire axial direction than the block main body and extending to one side in a tire circumferential direction, a projection is provided between two fin portions of said at least two fin portions on the base surface, the projection is disposed within a block adjacent region which includes a gap portion between the two fin portions and an extension portion extending from the gap portion toward a heel side in the designated rotation direction so as to be parallel to the tire circumferential direction, the blocks include a crown block on a tire equator side and a middle block adjacent to the crown block in the tire axial direction, and characterized in that each of the crown block and the middle block is formed as the finned block, wherein the crown block includes three fin portions including a first fin portion on one side in the tire axial direction, a second fin portion on the other side in the tire axial direction, and a third fin portion between the first fin portion and the second fin portion, and wherein the middle block includes the two fin portions including a first fin portion on one side in the tire axial direction and a second fin portion on the other side in the tire axial direction, one projection is disposed in each of the block adjacent region between the first fin portion and the third fin portion and the block adjacent region between the second fin portion and the third fin portion of the crown block, and one projection is disposed in the block adjacent region between the first fin portion and the second fin portion of the middle block.