To obtain a riveting device which is operated according to the principle of a synchronous shock, is simpler than that manufactured by a usual technology, is smaller, can be easily used, and is inexpensive.

A realize the device, two riveting set assembly bodies 14 are mounted respectively on carrying devices 4 and 5 making it possible to be effectors mounted on robot arms A and B on each side of work-pieces 2 and 3 to be combined by riveting. On each carrying device, an electric motor 21 driving in parallel the riveting set assembly body, for instance, through ball screws 18 and 19, preferably a driving means consisting of a brushless motor, is provided. A control means 25 is designed to operate the two motors 21 so that while preventing the occurrence of an undesirable movement and a stress in the work-piece to be combined, the riveting set 14 hits with a time lag and/or with a difference in kinetic energy selected to form a rivet in a desired state.