[PROBLEMS] plan to use close-up and further improve the safety performance or accuracy as Safe, by increasing the target reliability of the push-push type latch mechanism. [MEANS FOR SOLVING PROBLEMS movable part (2) the body (1) against the carbon paper strength against and to the forward foot jammed, the position of the body (1) by operating a push, again pushes the movable body in this state, by operating to be used with the latch device (3) of the push-push type, which can release the engaging state, is formed on either side of the main body 1 and the movable body (2) reciprocating groove (f) and home circular cam having an engagement groove (h) (40), is formed at the other side provided with a responsive (應 動) member 41 having a pin 45 that traces a circular cam groove 40, and the response Eastern material ( 41) by the return impossible to implement a latching groove (h) the pin (45) when receiving a load such as impact from the round groove (f) of the circular cam groove 40, if the locking state of the latch device 3 even if released by such shock loads and maintains the movable member (2) in the fixed position.