A seat reclining apparatus (10, 60) for a vehicle, comprising: a first arm (11, 61) configured to be fixedly attached to one of a seat cushion and a seatback; a second arm (12, 66) configured to be fixedly attached to the other one of the seat cushion and the seatback, the second arm (12, 66) rotatably supported by the first arm (11, 61); a pawl (31 A, 31B, 31C, 80), of which movement in a radial direction is guided by a guide wall (51, 63, 64) provided at the first arm (11, 61), including external teeth (44, 47, 82) which are provided at a radially outer surface of the pawl (31 A, 31 B, 31C, 80) and are engageable with internal teeth provided at the second arm (12, 66), the pawl (31 A, 31 B, 31C, 80) including a cam portion (45, 48, 83) formed at a radially inner surface of the pawl (31 A, 31 B, 31C, 80) and a plurality of pawl-side cam surfaces (50a, 50b, 50c, 83a, 83b) arranged at the cam portion (45, 48, 83) in a circumferential direction of the cam portion (45, 48, 83); a cam (32, 100) engaging with the pawl (31 A, 31 B, 31C, 80) and rotatably provided at a central portion of the first arm (11, 61), the cam (32, 100) including a cam surface (55, 101) engaging with the cam portion (45, 48, 83) formed at the pawl (31 A, 31 B, 31C, 80); and a biasing member (34, 120) biasing the cam (32, 100) to rotate in one direction and causing the cam surface (55, 101) to press the cam portion (45, 48, 83) in a radial direction in which the external teeth (44, 47, 82) and the internal teeth engage with each other, characterized in that the plurality of pawl-side cam surfaces (50a, 50b, 50c, 83a, 83b) or the cam surface (55, 101) is configured in a manner that the plurality of pawl-side cam surfaces (50a, 50b, 50c, 83a, 83b) and the cam surface (55, 101) are in contact with each other when the external teeth (44, 47, 82) and the internal teeth are in an engaged state and in a manner that clearances, which are generated between each of the plurality of pawl-side cam surfaces (50a, 50b, 50c, 83a, 83b) and the cam surface (55, 101) in the radial direction when the pawl (31 A, 31 B, 31C, 80) is moved by a rotational operation of the cam (32, 100) against a biasing force of the biasing member (34, 120) in the radial direction in which the engaged state of the external teeth (44, 47, 82) and the internal teeth is released, are all uniform. a first arm (11, 61) configured to be fixedly attached to one of a seat cushion and a seatback; a second arm (12, 66) configured to be fixedly attached to the other one of the seat cushion and the seatback, the second arm (12, 66) rotatably supported by the first arm (11, 61); a pawl (31 A, 31B, 31C, 80), of which movement in a radial direction is guided by a guide wall (51, 63, 64) provided at the first arm (11, 61), including external teeth (44, 47, 82) which are provided at a radially outer surface of the pawl (31 A, 31 B, 31C, 80) and are engageable with internal teeth provided at the second arm (12, 66), the pawl (31 A, 31 B, 31C, 80) including a cam portion (45, 48, 83) formed at a radially inner surface of the pawl (31 A, 31 B, 31C, 80) and a plurality of pawl-side cam surfaces (50a, 50b, 50c, 83a, 83b) arranged at the cam portion (45, 48, 83) in a circumferential direction of the cam portion (45, 48, 83); a cam (32, 100) engaging with the pawl (31 A, 31 B, 31C, 80) and rotatably provided at a central portion of the first arm (11, 61), the cam (32, 100) including a cam surface (55, 101) engaging with the cam portion (45, 48, 83) formed at the pawl (31 A, 31 B, 31C, 80); and a biasing member (34, 120) biasing the cam (32, 100) to rotate in one direction and causing the cam surface (55, 101) to press the cam portion (45, 48, 83) in a radial direction in which the external teeth (44, 47, 82) and the internal teeth engage with each other, characterized in that the plurality of pawl-side cam surfaces (50a, 50b, 50c, 83a, 83b) or the cam surface (55, 101) is configured in a manner that the plurality of pawl-side cam surfaces (50a, 50b, 50c, 83a, 83b) and the cam surface (55, 101) are in contact with each other when the external teeth (44, 47, 82) and the internal teeth are in an engaged state and in a manner that clearances, which are generated between each of the plurality of pawl-side cam surfaces (50a, 50b, 50c, 83a, 83b) and the cam surface (55, 101) in the radial direction when the pawl (31 A, 31 B, 31C, 80) is moved by a rotational operation of the cam (32, 100) against a biasing force of the biasing member (34, 120) in the radial direction in which the engaged state of the external teeth (44, 47, 82) and the internal teeth is released, are all uniform.