PURPOSE: To simply and surely conduct the operation by immovably fixing a forward hang grip to a driving source, rotatably supporting a rearward hand grip to a carrier part of the driving source, and providing at least either the carrier part or the rearward hand grip with a releasable locking means for automatically locking in a specified work position.

CONSTITUTION: A rearward hand grip 3 is similarly gripped by the hand regardless of the work position of a work machine, so that a lever and a switch provided in the rearward hand grip 3 always occupy the same positions in an operator's hand, and further unexpected adjustment from the work position can be prevented by a locking means (comprising a lock claw 15 and a projecting part 17) automatically locked by mutual engagement to constrain the form.