SEAT RECLINING DEVICE AND SEAT DEVICE

A memory mechanism (50) is provided with engagement portions (53A, 53B), a housing recess (51), a memory plate (52), and engagement receiving portions (52A, 52B). The engagement portions (53A, 53B) are provided to an adjacent pair of pawls (35), respectively. The housing recess (51) has a cylindrical shape and is provided to a first member (31). The memory plate (52) is formed in an annular shape which is cut at one point. The memory plate (52) is housed within the housing recess (51) while being reduced in diameter with the cut portion (S) disposed between the engagement portions (53A, 53B). The engagement receiving portions (52A, 52B) are respectively adjacent between the engagement portions (53A, 53B) of the memory plate (52), to the engagement portions (53A, 53B). The engagement portions (53A, 53B) are engaged with and disengaged from the engagement receiving portions (52A, 52B) as the pawls (35) move in the radial direction.