A child protector mechanism includes a base member, a first lever, a second lever, a bush arranged between the first lever and the second lever, a child protector lever for moving the bush to an unset position or a set position, and a position retaining mechanism provided between the first lever and the bush. The bush is retained at each of the unset position and the set position by the position retaining mechanism provided between the first lever and the bush. Therefore, when assembling the bush and the first lever to the base member, the bush is retained at a predetermined position (for example, unset position) with respect to the first lever so that the bush does not move. Thus, the easiness of assembly of the bush and the first lever and the easiness of assembly of the child protector lever are excellent.