To perform jump-out and pull-in of a push plate during change of a tool without depending on an energizing spring to energize a guide bar.

A bush plate 14 in which a bush 16 is fitted is arranged at the tip of a guide bar 19 and a cylinder 24 to move forward and backward the guide bar 19 is arranged. A hook 29, a contact member 30, and an energizing spring 31 are inserted in the staged hole 27 of the guide bar 19. During normal use, the bush plate 14 is energized through the force of an energizing spring 31 and during change of a tool, the energizing spring 31 is held by the hook 29 and the contact member 30 and the bush plate 14 is relatively moved forward and backward to and from a body 7 by the cylinder 24.