A catcher 2 includes a catcher stopper 21, a holder 22 for a striker 1, and a biasing member 23 for the catcher stopper and the holder. When the catcher stopper 21 is projected by the biasing member 23, the holder 22 is set in a forward position and in a non-holding state, and when the holder 22 is set in a backward position and in a holding state, the catcher stopper 21 is withdrawn. The recess Mb has an engageable hole 402 formed therein for engagement with the catcher stopper 21, and a force is stored in the biasing member 3 when the catcher 2 is set in a reference position where the catcher stopper 21 is brought into engagement with the engageable hole 402. The sticker 1 enters the holder 22 of the catcher 2 when the catcher is set in the reference position since the movable member M is moved forward to a self-propelled movement start position.