Wobbling among components is reduced. The seat reclining device includes: outer rolling members (80) disposed between a ring-shaped bottom surface portion (71) of a mounting ring (70) and an outer surface of a guide bracket (20) or an outer surface of an internal gear (30), that faces the ring-shaped bottom surface portion (71); and inner rolling members (90) which are disposed between opposed surfaces of guide groove portions of the guide bracket (20) and lock plates (60A to 60D) to guide the lock plates (60A, 60C) in a radial direction. Owing to the outer rolling members (80) and the inner rolling members (90), force pressing stacked members relatively to one another functions in a stacking direction, and as its reaction force, spring force of the mounting ring (70) acts, so that wobbling is reduced. As for the relative pressing force by the outer rolling members (80) and the inner rolling members (90), the pressing force by the rolling members (80, 90) acts not only in a locked state but also in an unlocked state, so that wobbling among the members is reduced in the both states.