A tire (1, 1A, 1B) for heavy duty comprising: a tread section including a circumferential groove formed to extend in a tire circumferential direction, and a lug groove formed to have an opening portion at a tread end which is an outer-side end of the tread section and to extend in a tread width direction from the tread end to the circumferential groove; and a projection part provided on a groove bottom of the circumferential groove, wherein the circumferential groove is formed at a position shifted by TW/8 from a tire center line outward in the tread width direction, where TW denotes a width of the tread section in the tread width direction, the projection part extends from one of side walls forming the circumferential groove to the other side wall opposed to the one side wall, a plurality of the lug grooves are formed at a predetermined interval in the tire circumferential direction, given that an intersection is a point where a circumferential groove inner line passing through an inside of the circumferential groove crosses a lug groove inner line passing through an inside of each of the lug grooves in a tread face view of the tire (1, 1A, 1B), the projection part is provided between a first intersection and a second intersection next to the first intersection in the tire circumferential direction, the second intersection is located behind the first intersection in a tire rotation direction, the projection part is provided on the second intersection side of a point shifted by PL/4 from the first intersection, where PL denotes an interval between the first intersection and the second intersection, and the projection part is provided on a forward side, in a tire rotation direction, of a point shifted by 3PL/4 from the first intersection. a tread section including a circumferential groove formed to extend in a tire circumferential direction, and a lug groove formed to have an opening portion at a tread end which is an outer-side end of the tread section and to extend in a tread width direction from the tread end to the circumferential groove; and a projection part provided on a groove bottom of the circumferential groove, wherein the circumferential groove is formed at a position shifted by TW/8 from a tire center line outward in the tread width direction, where TW denotes a width of the tread section in the tread width direction, the projection part extends from one of side walls forming the circumferential groove to the other side wall opposed to the one side wall, a plurality of the lug grooves are formed at a predetermined interval in the tire circumferential direction, given that an intersection is a point where a circumferential groove inner line passing through an inside of the circumferential groove crosses a lug groove inner line passing through an inside of each of the lug grooves in a tread face view of the tire (1, 1A, 1B), the projection part is provided between a first intersection and a second intersection next to the first intersection in the tire circumferential direction, the second intersection is located behind the first intersection in a tire rotation direction, the projection part is provided on the second intersection side of a point shifted by PL/4 from the first intersection, where PL denotes an interval between the first intersection and the second intersection, and the projection part is provided on a forward side, in a tire rotation direction, of a point shifted by 3PL/4 from the first intersection.