A pneumatic tire where a pair of center main grooves (12, 13) extending in the tire circumferential direction are provided on both sides of an equatorial plane of the tire in a tread portion, a shoulder main groove (11, 14) extending in the tire circumferential direction is provided on an outer side in the tire width direction of each center main groove (12, 13), a center land portion is demarcated between the center main grooves (12, 13), a middle land portion (22, 24) is demarcated on the center main groove (12, 13) and the shoulder main groove (11, 14), a shoulder land portion (21, 25) is demarcated on the outer side in the tire width direction of the shoulder main groove (11, 14), a plurality of lug grooves (31, 35) extending in the tire width direction are provided in each shoulder land portion (21, 25) at intervals in the tire circumferential direction, wherein from the viewpoint of the tire meridian cross section, when a standard profile line forming an arc that passes through both endpoints in the tire width direction of the pair of center main grooves (12, 13) is assumed, a profile line that defines the road contact surface of the center land portion protrudes to the outer side in the tire radial direction than does the standard profile line, and a profile line that includes both endpoints in the tire width direction of the shoulder main grooves (11, 14) and the outer endpoint in the tire width direction of the center main groove (12, 13), and that defines the road contact surface of the middle land portion (22, 24) and the shoulder land portion (21, 25) protrudes further to the outer side in the tire radial direction than does the standard profile line, characterized in that the pitch of these lug grooves (31, 35) is changed on the tire circumference in a way and in that the ratio of the groove volume of the lug grooves (31, 35) to the size of the pitch of these lug grooves (31, 35) in the shoulder land portion (21, 25) decreases as the pitch increases, and increases as the pitch decreases, wherein the maximum projection amount to the outer side of the tire radial direction of the profile line of the shoulder land portion (21, 25) and the middle land portion (22, 24) with respect to the standard profile line is from 0.6 to 2.0 mm and wherein a mounting direction to the vehicle is specified, wherein the maximum projection amount to the outer side in the tire radial direction of the profile line of the shoulder land portion (21, 25) and the middle land portion (22, 24) with respect to the standard profile line is relatively larger on the outer side of the vehicle than on the inner side of the vehicle. a pair of center main grooves (12, 13) extending in the tire circumferential direction are provided on both sides of an equatorial plane of the tire in a tread portion, a shoulder main groove (11, 14) extending in the tire circumferential direction is provided on an outer side in the tire width direction of each center main groove (12, 13), a center land portion is demarcated between the center main grooves (12, 13), a middle land portion (22, 24) is demarcated on the center main groove (12, 13) and the shoulder main groove (11, 14), a shoulder land portion (21, 25) is demarcated on the outer side in the tire width direction of the shoulder main groove (11, 14), a plurality of lug grooves (31, 35) extending in the tire width direction are provided in each shoulder land portion (21, 25) at intervals in the tire circumferential direction, wherein from the viewpoint of the tire meridian cross section, when a standard profile line forming an arc that passes through both endpoints in the tire width direction of the pair of center main grooves (12, 13) is assumed, a profile line that defines the road contact surface of the center land portion protrudes to the outer side in the tire radial direction than does the standard profile line, and a profile line that includes both endpoints in the tire width direction of the shoulder main grooves (11, 14) and the outer endpoint in the tire width direction of the center main groove (12, 13), and that defines the road contact surface of the middle land portion (22, 24) and the shoulder land portion (21, 25) protrudes further to the outer side in the tire radial direction than does the standard profile line, characterized in that the pitch of these lug grooves (31, 35) is changed on the tire circumference in a way and in that the ratio of the groove volume of the lug grooves (31, 35) to the size of the pitch of these lug grooves (31, 35) in the shoulder land portion (21, 25) decreases as the pitch increases, and increases as the pitch decreases, wherein the maximum projection amount to the outer side of the tire radial direction of the profile line of the shoulder land portion (21, 25) and the middle land portion (22, 24) with respect to the standard profile line is from 0.6 to 2.0 mm and wherein a mounting direction to the vehicle is specified, wherein the maximum projection amount to the outer side in the tire radial direction of the profile line of the shoulder land portion (21, 25) and the middle land portion (22, 24) with respect to the standard profile line is relatively larger on the outer side of the vehicle than on the inner side of the vehicle.