Abstract: An objective of the invention is to provide a work apparatus in which the maximum value of the force acting on a work object is unchanged even when the size of the object varies, the work apparatus not exerting force in excess of a prescribed value. The work apparatus is provided with a first member (1) and a second member (2), at least one of which is moveable, and is additionally provided with a work part (3) operated by movement of the first member (1) or the second member (2). Either the first member (1) or the second member (2) is furnished with a mobilization part (4) and a mobilized contact part (5), while the other is furnished with a contact receiving part (6).