Fast clamping mechanism with cam

The utility model relates to a clamping device, in particular to a fast clamping mechanism with a cam. The fast clamping mechanism with the cam comprises a base, a pressing plate with a clamping head, the cam, a compression spring, a supporting table and a bolt with the lower end connected with the base. The bolt is arranged in the middle of the pressing plate in a sleeved mode, and a pressing nut is arranged at the upper end of the bolt. The compression spring is arranged on a screw rod between the pressing plate and the base in a sleeved mode. The supporting table is arranged at one end, far away from the clamping head, of the base. The cam is hinged to one end, far away from the clamping head, of the pressing plate and abuts against the upper surface of the supporting table. When the fast clamping mechanism with the cam is used for clamping work-pieces, the cam is automatically locked, force does not need to be exerted on the force exertion end continuously, and therefore the processing efficiency is impro