To provide a vehicle seat reclining device that can ensure sufficient lock strength and causes sliding of poles upon tilting of a seatback along with memory actuation to be more smooth while adding a memory function of tilting angles of the seatback.

The pole 31C includes an engagement projection part 49B provided to project in an axial direction opposed to a memory plate 76. The memory plate 76 is disposed at a position different from positions of outer teeth 44 and 47 of the poles 31A to 31C in the axial direction and has a memory cam surface 76a, which opens a circumferential movement trajectory of an engagement projection part 49C upon unlocking actuation of a cam 32, etc. caused along memory actuation of a trigger plate 71 and also locks movement of the pole 31C to the side in which the outer teeth 47 are engaged with inner teeth 22 by sliding the engagement projection part 49C upon relative rotation of a lower arm 10 and an upper arm 20 integrated with the memory plate 76.