Seat reclining device

A seat reclining device comprising:

• a first gear member which includes a boss portion formed on an inner peripheral side and one of an internal gear and an external gear formed on an outer peripheral side;
• a second gear member which includes an inner peripheral surface portion formed on an inner peripheral side and forming an eccentric space together with an outer peripheral surface of the boss portion and the other one of the internal gear and the external gear formed on an outer peripheral side;
• paired wedge members which are arranged in the eccentric space;
• a biasing member which biases the paired wedge members in directions away from each other;
• and
• a drive member which includes a shaft portion rotatably supported on an inner peripheral surface of the boss portion, wherein
• the drive member includes a first drive protrusion which is arranged in a small-width portion of the eccentric space and a second drive protrusion which is arranged in a large-width portion of the eccentric space, and
• when the drive member rotates the paired wedge members, counterforce acting on the shaft portion of the drive member against first pressing force generated by the first drive protrusion pressing one of the paired wedge members and second pressing force generated by the second drive protrusion pressing the other one of the paired wedge members pushes the boss portion of the first gear member in a direction toward the one wedge member.