A pneumatic tire (10, 20, 30, 40, 50) for heavy load comprising, on a tread surface of the tire (10, 20, 30, 40, 50), land portions defined by a plurality of lug grooves each extending in the tread width direction while opening at one end thereof to the tread ground-contact end, wherein: the tire (10, 20, 30, 40, 50) has a negative ratio Nc of 2% to 10% in a tread center side region (Rc) which corresponds to a tread region having a width that accounts for 30% of the tread ground-contact width Tw with the tire equator being in the center in the tread width direction; the lug groove has a depth da, the land portion has a width Rw, where the land portion width Rw is defined for each arbitrary point on a land portion center line P, and the land portion width Rw on the point refers to a width in an end view taken along a plane that passes through the point and is perpendicular to the land portion center line P, and the land portion has an extending length L which is a length of the land portion center line P connecting the midpoints of the tread circumferential width of the land portion between the tire equator and the tread ground-contact end, so that the land portion center line P has a length of 0.5 L or more in a segment where Rw/da is 1.3 to 2.5; the land portion center line P has a length of 0.3 L or more in a segment having a tilt angle α of 60° or less relative to the tire equator direction; and the land portion center line P has a plurality of land portion center line segments (P1, P2) extending in different directions, among which a segment positioned on the tread width direction outside has, relative to the tire equator direction, a tilt angle (α2) that is smaller as compared with a tilt angle (α1), relative to the tire equator direction, of a segment positioned on the tire equator side. the tire (10, 20, 30, 40, 50) has a negative ratio Nc of 2% to 10% in a tread center side region (Rc) which corresponds to a tread region having a width that accounts for 30% of the tread ground-contact width Tw with the tire equator being in the center in the tread width direction; the lug groove has a depth da, the land portion has a width Rw, where the land portion width Rw is defined for each arbitrary point on a land portion center line P, and the land portion width Rw on the point refers to a width in an end view taken along a plane that passes through the point and is perpendicular to the land portion center line P, and the land portion has an extending length L which is a length of the land portion center line P connecting the midpoints of the tread circumferential width of the land portion between the tire equator and the tread ground-contact end, so that the land portion center line P has a length of 0.5 L or more in a segment where Rw/da is 1.3 to 2.5; the land portion center line P has a length of 0.3 L or more in a segment having a tilt angle α of 60° or less relative to the tire equator direction; and the land portion center line P has a plurality of land portion center line segments (P1, P2) extending in different directions, among which a segment positioned on the tread width direction outside has, relative to the tire equator direction, a tilt angle (α2) that is smaller as compared with a tilt angle (α1), relative to the tire equator direction, of a segment positioned on the tire equator side.