To stably move and position a work without basing on a reaction distance after the work is brought into contact with the striking part of a striking device till a robot is stopped.

The robot 15 for which the work W is freely moved in the back, forth, right and left directions is provided. The striking device provided with a striking pad 59, moving part and detecting part is provided. When the work W is struck to the striking pad 59 of the striking device with the robot 15, the moving part is worked and it is detected with the detecting part. The 'reaction distance' after the command for stopping the robot 15 is issued by the detecting signal till the robot is actually stopped is beforehand stored in a controller as a parameter. The 'relative position of the work' for expressing the position where the work W is held with the robot 15 based on the 'reaction distance' is calculated and, based on this 'relative position of the work', the work W is accurately positioned in the prescribed position of the die.