PURPOSE: To perform switching operation of a two-position switching type operation lever, such as a forward/reverse switching lever, in any operation position without releasing a hand from a handle.

CONSTITUTION: In a binder having a forward reverse switching lever energized to an upper forward position F, a lever 7 is pressed down against the force of a winding spring 9 by a thumb by which a grip part 5b is gripped. A moving route 11 is arranged to a holding member 12 on the handle side and a pin 13 fitted in the moving route 11 is arranged to the lever 7. Upper and lower root positions (d) and (b) in which the position of the pin 13 is held by means of the wind spring 9 are positioned in the moving route 11 and the pin is positioned between the two root positions (d) and (b). Right and left crest positions (c) and (a) over which the pin 13 is moved through operation of a lever in a direction in which it is against the force of the winding spring 9 are formed in the moving route 11. This constitution constitutes a switching mechanism K of one-way steering structure such that an advance position F is provided when the pin 13 is located in the lower root (b) and a reverse position R is provided when the pin 13 is positioned at the upper root (d).