A pneumatic tire having a designated mounting orientation with respect to a vehicle, wherein a tread portion comprises: a pair of center longitudinal grooves which continuously extends in a circumferential direction on both sides of a tire equator; and a pair of shoulder longitudinal grooves which continuously extends in the circumferential direction on both sides of the pair of center longitudinal grooves; the pair of center longitudinal grooves consists of an outer center longitudinal groove and an inner center longitudinal groove, the outer center longitudinal groove and the inner center longitudinal groove being respectively located on an outer side and an inner side of the vehicle when the tire is mounted to the vehicle, the pair of shoulder longitudinal grooves consists of an outer shoulder longitudinal groove disposed on the vehicle outer side of the outer center longitudinal groove and an inner shoulder longitudinal groove disposed on a vehicle inner side of the inner center longitudinal groove, the tread portion is divided into: a center land portion between the pair of center longitudinal grooves; an outer middle land portion between the outer center longitudinal groove and the outer shoulder longitudinal groove; an inner middle land portion between the inner center longitudinal groove and the inner shoulder longitudinal groove; an outer shoulder land portion located of the vehicle outer side of the outer shoulder longitudinal groove; and an inner shoulder land portion located of the vehicle inner side of the inner shoulder longitudinal groove, characterized in that the outer shoulder land portion comprises an array of blocks in which outer shoulder blocks sectioned by outer shoulder lateral grooves are disposed in the circumferential direction, the outer shoulder lateral grooves extend from a vehicle-outer-side tread ground-contact end to the inner side of the vehicle and traverse the outer shoulder land portion, the inner shoulder land portion comprises inner shoulder lateral grooves and inner shoulder auxiliary grooves, the inner shoulder lateral grooves extending to the outer side of the vehicle from an inner end which is spaced from a vehicle-inner-side tread ground-contact end to the outer side of the vehicle and having an outer end terminating within the inner shoulder land portion, the inner shoulder auxiliary grooves being disposed between the inner shoulder lateral grooves which are circumferentially adjacent to each other, extending to the outer side of the vehicle from an inner end which is spaced from the vehicle-inner-side tread ground-contact end to the outer side of the vehicle, and having an outer end terminating within the inner shoulder land portion, and the inner middle land portion comprises an inner middle sub-groove and inner middle sipes, the inner middle sub-groove continuously extends in the circumferential di recti on at a position which is on the vehicle inner side of a width center of the inner middle land portion, and the inner middle sipes extend between the inner middle sub-groove and the inner center longitudinal groove with an inclination with respect to the circumferential direction. a pair of center longitudinal grooves which continuously extends in a circumferential direction on both sides of a tire equator; and a pair of shoulder longitudinal grooves which continuously extends in the circumferential direction on both sides of the pair of center longitudinal grooves; a center land portion between the pair of center longitudinal grooves; an outer middle land portion between the outer center longitudinal groove and the outer shoulder longitudinal groove; an inner middle land portion between the inner center longitudinal groove and the inner shoulder longitudinal groove; an outer shoulder land portion located of the vehicle outer side of the outer shoulder longitudinal groove; and an inner shoulder land portion located of the vehicle inner side of the inner shoulder longitudinal groove, the inner shoulder lateral grooves extending to the outer side of the vehicle from an inner end which is spaced from a vehicle-inner-side tread ground-contact end to the outer side of the vehicle and having an outer end terminating within the inner shoulder land portion, the inner shoulder auxiliary grooves being disposed between the inner shoulder lateral grooves which are circumferentially adjacent to each other, extending to the outer side of the vehicle from an inner end which is spaced from the vehicle-inner-side tread ground-contact end to the outer side of the vehicle, and having an outer end terminating within the inner shoulder land portion, and the inner middle sub-groove continuously extends in the circumferential di recti on at a position which is on the vehicle inner side of a width center of the inner middle land portion, and the inner middle sipes extend between the inner middle sub-groove and the inner center longitudinal groove with an inclination with respect to the circumferential direction.