<p>A seat reclining apparatus includes a fine angle adjustment mechanism for finely adjusting an angle between a seat cushion and a seat back of a seat and including a planetary gear mechanism having a first gear provided to a seat cushion side of the seat for relative rotation with the seat cushion and a second gear fixed to a seat back side of the seat and an engaging/disengaging mechanism for controlling the relative rotation between the seat cushion and the seat back of the seat and including a base plate fixed to the seat cushion side and a stopper member provided to the base plate and engageable with or disengageable from the first gear. The relative rotation of the first gear with respect to the seat cushion is restricted when the stopper member engages with the first gear and the relative rotation of the first gear to the seat cushion is allowed when the stopper member disengages from the first gear. The seat reclining apparatus is characterized in that a first shaft for inputting an operating force to the fine adjustment mechanism is arranged approximately coaxially with a second shaft for transmitting an operating force to the engaging/disengaging mechanism.</p>