A seat reclining apparatus includes a pair of first arms, a pair of second arms, a pair of hinge pins, a pair of reclining mechanisms including a pair of lock mechanisms, each of which includes a cam, the lock mechanism restricting a rotational movement of the seat back relative to the seat cushion and releasing a restriction of the rotational movement, by means of a rotational movement of the hinge pins and the cams, and a connecting member provided between the reclining mechanisms and connected to the hinge pins, wherein each of the hinge pins is structured so as to be inserted into each of the reclining mechanisms from an inward of the seat, and a connecting portion is provided at an inner end of at least one of the hinge pins facing the other one of the hinge pins and is connected to the connecting member.