Neigungsverstellvorrichtung für einen Sitz

To minimize the width of a seat reclining device (1) provided with a Taumel mechanism (30) (planetary gear type angle adjusting mechanism), a motor unit (40) is disposed on an inside surface of a base frame (10) and within a seat cushion, and a motor output gear is disposed on an opposite outside surface of the base frame. Further, an outer gear of Taumel mechanism (30) is formed in the base frame; an inner gear of the Taumel mechanism (30) is formed in a reclining arm (20) in mesh with the outer gear; and the reclining arm (20) is disposed on the inside surface of the base frame (10) and the reclining gear (50) is disposed on the opposite outside surface of the base frame (10). Further, a shock absorbing member is disposed at the reclining gear (50) to effectively absorb shock generated when the seat back is tilted to its extreme position stoppers.