To provide a cramping device capable of placing a work at a predetermined position by preventing the work from levitating during cramping.

The cramping device cramps the work on a reference surface so as to be caught in with a plurality of cramp members comprising a cramp member main body and a cramp part which is integral with or separate from the cramp member main body and provided so as to be elastically displaceable. The cramp part is reset in one direction during unclamping, elastically displaced in the other direction until it is abuts on the cramp part main body during the cramping, and the work is thereby cramped while pressed on the reference surface.