A pneumatic tire is provided on the tread portion (2) with a pair of crown circumferential grooves (3) that extending on either side of the tire equator (C); a pair of shoulder circumferential grooves (4) each extending between the crown circumferential groove (3) and a ground-contacting end (2t); a crown rib (5) extending between the crown circumferential grooves (3); middle ribs (6) each extending between the crown circumferential grooves (3) and the shoulder circumferential grooves (4); and shoulder ribs (7) each extending between the shoulder circumferential groove (4) and the ground-contacting end (2t). The groove volume ratio Rc of the crown rib, which is a ratio of the total volume of the grooves and sipes provided on the crown rib to the rib volume of the crown rib (5), the groove volume ratio Rm of the middle rib (6), and the groove volume ratio Rs of the shoulder rib (7) satisfy the relationship, Rc