Child seat and shoulder adjuster

In order to easily adjust the height of webbings (25) of a child seat (20) from either the front or rear side, manipulation pieces (50) are caused to move in a direction approaching each other by fingers. With the approaching movement of the manipulation pieces (50), locking pieces (47) are caused to move in a direction approaching each other, and the respective leading ends of the locking pieces (47) then come out of the locking holes (71). Thus, when the manipulation pieces (50) are maintained in this state, a sliding block (40) is caused to move in the vertical direction. After viewing marks of longitudinal grooves (59) through a window hole (36), or at a desired height where the marks (61) and indicators (77) coincide with each other, the fingers are released from the manipulation pieces (50). As a result, the manipulation pieces (50) are pressed and advanced by coil springs (56) until they abut on the partition walls (42). Also, the locking pieces (47) are advanced, and thus their respective leading ends are inserted into the locking holes (71).