Six track grooves (7) formed in a spherical inner peripheral surface (6) of an outer joint member (2) are each formed into an arc shape having a curvature center at a joint center (O) . The track grooves (7) are inclined in a circumferential direction of the outer joint member (2) with respect to a joint axial line (N-N), and are adjacent to each other in the circumferential direction with their inclination directions opposite to each other. Six track grooves (9) formed in a spherical outer peripheral surface (8) of an inner joint member (3) are formed so as to be mirror-image symmetrical with the track grooves (7) paired therewith of the outer joint member (2) with respect to a joint center plane (P) at an operating angle of 0°. An inclination angle (γ) of each of the track grooves (7) of the outer joint member (2) with respect to the joint axial line (N-N) is set to 8° or more and 16° or less.