To provide a device for working a workpiece, which deals with the high-mix low-volume production of workpiece accompanying the changeover of the kind of a machine for the workpiece.

A clamp holding device 29 is moved by a third moving mechanism so that a clamping tool 32 which is selected corresponding to a workpiece PW which is a pipe material to be worked is moved to a working position, and the supporting device body 2A of a punching tool supporting device 2 is moved by a first moving mechanism so that a selected punching tool 8 of a plurality of the punching tools 8 is moved to a predetermined position and also the selected punching tool 8 which is moved to the predetermined position is moved to the position for working the workpiece PW by a second moving mechanism, and the workpiece PW which is held by the selected clamping tool 32 is worked with the selected punching tool 8 which is moved to the predetermined position.