A pneumatic tire comprising, on a tread surface, a plurality of circumferential main grooves extending in a tread circumferential direction, and a plurality of land portions, each land portion being defined between circumferential main grooves adjacent in a tread width direction among the plurality of circumferential main grooves, or by the circumferential main groove and a tread edge, wherein at least one land portion includes a plurality of widthwise grooves extending in the tread width direction and a plurality of widthwise sipes extending in the tread width direction, each widthwise groove includes a gradually decreasing groove width portion in which the groove width gradually decreases from the tread surface towards an inner side in a tire radial direction, a constant groove width portion that extends from the gradually decreasing groove width portion towards the inner side in the tire radial direction and has a substantially constant groove width, and a branched groove portion that branches and extends from the constant groove width portion towards the inner side in the tire radial direction, characterised in that each widthwise sipe includes a gradually decreasing sipe width portion in which a sipe width gradually decreases from the tread surface towards an inner side in the tire radial direction, a constant sipe width portion that extends from the gradually decreasing sipe width portion towards the inner side in the tire radial direction and has a substantially constant sipe width, and a branched sipe portion that branches and extends from the constant sipe width portion towards the inner side in the tire radial direction, wherein the constant groove width portion may include a portion in which the groove width varies slightly, as long as the difference between the maximum and minimum values of the groove width of the constant groove width portion is 0.2 mm or less, and wherein the constant sipe width portion may include a portion in which the sipe width varies slightly, as long as the difference between the maximum and minimum values of the sipe width of the constant sipe width portion is 0.2 mm or less. at least one land portion includes a plurality of widthwise grooves extending in the tread width direction and a plurality of widthwise sipes extending in the tread width direction, each widthwise groove includes a gradually decreasing groove width portion in which the groove width gradually decreases from the tread surface towards an inner side in a tire radial direction, a constant groove width portion that extends from the gradually decreasing groove width portion towards the inner side in the tire radial direction and has a substantially constant groove width, and a branched groove portion that branches and extends from the constant groove width portion towards the inner side in the tire radial direction, characterised in that each widthwise sipe includes a gradually decreasing sipe width portion in which a sipe width gradually decreases from the tread surface towards an inner side in the tire radial direction, a constant sipe width portion that extends from the gradually decreasing sipe width portion towards the inner side in the tire radial direction and has a substantially constant sipe width, and a branched sipe portion that branches and extends from the constant sipe width portion towards the inner side in the tire radial direction, wherein the constant groove width portion may include a portion in which the groove width varies slightly, as long as the difference between the maximum and minimum values of the groove width of the constant groove width portion is 0.2 mm or less, and wherein the constant sipe width portion may include a portion in which the sipe width varies slightly, as long as the difference between the maximum and minimum values of the sipe width of the constant sipe width portion is 0.2 mm or less.