A seat reclining apparatus for a vehicle includes first, second, and third gear mechanisms, each gear mechanism including a first frame having an internal gear and a second frame having an external gear engaging with the internal gear, the number of teeth of the external gear being fewer than the internal gear, wherein the first gear mechanism is provided at one side of a vehicle seat, and the second and third gear mechanisms are provided at the other side, a shaft connecting the first gear mechanism with the second and third gear mechanisms, and an electric motor rotating the shaft to shift an engagement position between the internal gear and the external gear for tilting the seatback relative to the seat cushion, wherein the electric motor is disposed at one of the first frame and the second frame of the first gear mechanism provided at the one side.