To provide a ratchet mechanism with high quietness property and flexibility of design.

A support part 25 for receiving force, that is, turning force acting on a tooth locking member 23 from a ratchet gear 21 and a follower 29 for displacing the tooth locking member 23 are separately provided. Consequently, the turning force does not act on the follower 29 and a cam 27. The tooth locking member 23 does not collide with the ratchet gear 21 by being displaced to a separation position separated from the ratchet gear 21. Accordingly, a ratchet mechanism 20 with high quietness property and flexibility of design can be obtained.