A pneumatic tire, comprising: a carcass formed of at least one carcass ply, the carcass ply formed of a carcass main body and a carcass folded-up portion, the carcass main body extending toroidally from a tread portion through a pair of sidewall portions to a pair of bead portions, and fixed to bead cores embedded in the bead portions, the carcass folded-up portion extending from the carcass main body and formed by folding up a circumference of the bead cores from a tire widthwise inner side to a tire widthwise outer side; a belt formed of one or more belt layers (6a, 6b) arranged on a tire radial outer side of a crown portion of the carcass; and bead fillers provided on a tire radial outer side of the bead cores, wherein: the bead fillers are provided such that at least a part thereof is sandwiched between the carcass main body and the carcass folded-up portion, and a side reinforcement layer is arranged on the tire widthwise outer side of the carcass main body, the side reinforcement layer formed of a treated member, the treated member formed by coating with rubber organic fiber cords extending parallel to ply cords of the carcass ply of the carcass main body, only on a sidewall portion of a half portion on one tire widthwise side partitioned by a tire equatorial plane, the half portion on the one tire widthwise side being on an outer side when mounted to a vehicle, wherein at an unloaded condition, when the pneumatic tire is mounted to an applicable rim corresponding to a standard rim of an applicable size according to the "JATMA Year Book" in Japan, the "ETRTO STANDARD MANUAL" in Europe, or the "TRA YEAR BOOK" in the United States of America, and when the pneumatic tire is applied with a prescribed internal pressure corresponding to a maximum load carrying capacity of the tire, a tire radial inner end of the side reinforcement layer is located on a side inner in the tire radial direction than a tire radial outermost position of a rim flange of the applicable rim, and a tire radial outer end of the side reinforcement layer overlaps the belt by 5 mm or more in a tire widthwise direction, characterised in that the tread portion has one or more circumferential main grooves (11, 12, 13) extending in a tire circumferential direction, and at an unloaded condition, when the pneumatic tire is mounted to the applicable rim and is applied with the prescribed internal pressure, a contact width of a tire widthwise outermost land portion partitioned by the one or more circumferential main grooves (11, 12, 13) and a tread edge on the outer widthwise side when mounted to a vehicle is 1 to 3 mm larger than a contact width of a tire widthwise outermost land portion partitioned by the one or more circumferential main grooves (11, 12, 13) and a tread edge on the inner widthwise side when mounted to a vehicle. the bead fillers are provided such that at least a part thereof is sandwiched between the carcass main body and the carcass folded-up portion, and a side reinforcement layer is arranged on the tire widthwise outer side of the carcass main body, the side reinforcement layer formed of a treated member, the treated member formed by coating with rubber organic fiber cords extending parallel to ply cords of the carcass ply of the carcass main body, only on a sidewall portion of a half portion on one tire widthwise side partitioned by a tire equatorial plane, the half portion on the one tire widthwise side being on an outer side when mounted to a vehicle, wherein at an unloaded condition, when the pneumatic tire is mounted to an applicable rim corresponding to a standard rim of an applicable size according to the "JATMA Year Book" in Japan, the "ETRTO STANDARD MANUAL" in Europe, or the "TRA YEAR BOOK" in the United States of America, and when the pneumatic tire is applied with a prescribed internal pressure corresponding to a maximum load carrying capacity of the tire, a tire radial inner end of the side reinforcement layer is located on a side inner in the tire radial direction than a tire radial outermost position of a rim flange of the applicable rim, and a tire radial outer end of the side reinforcement layer overlaps the belt by 5 mm or more in a tire widthwise direction, characterised in that the tread portion has one or more circumferential main grooves (11, 12, 13) extending in a tire circumferential direction, and at an unloaded condition, when the pneumatic tire is mounted to the applicable rim and is applied with the prescribed internal pressure, a contact width of a tire widthwise outermost land portion partitioned by the one or more circumferential main grooves (11, 12, 13) and a tread edge on the outer widthwise side when mounted to a vehicle is 1 to 3 mm larger than a contact width of a tire widthwise outermost land portion partitioned by the one or more circumferential main grooves (11, 12, 13) and a tread edge on the inner widthwise side when mounted to a vehicle.