To engage a trigger piece with an engaging member without the so-called looseness in response to an opening between a door frame and a sliding door, and to simply draw the sliding door near by a hand.

Forked interlocking members 20 are supported axially into a strike body 16, the engaging member 19 is engaged with one sites 48 of the interlocking members 20 while one end sections of an actuating member 35 are connected at the other sites of the interlocking members 20 through a movable shaft 21 or the like, the other end sections of the actuating member 35 are supported pivotally while being urged at all times in one direction by an urging spring 22 mounted in the strike body 16, and the front end section of the engaging member 19 has an engaging section 27, with which the front end section 8a of the trigger piece 8 under the state, in which the front end section 8a is pushed by the actuating member 35, is engaged even when a slight opening (a) is formed between the door frame 15 and the sliding door when the sliding door 1 is closed.