The utility model relates to a clamping device, include: the guide rail mount pad, two parallel and interval settings of guide rail of opening and shutting, the symmetry is equipped with the guide way respectively, and the guide way extends along the length direction slope of the guide rail that opens and shuts, two voussoir guide holders can be followed the range upon range of direction of two guide rails that open and shut and are close to each other or keep away from, are equipped with the leading wheel on two module guide holders respectively, and two sets of leading wheels can be followed the guide way and removed, one side that two voussoir guide holders are close to is each other located respectively to two voussoir chucks, actuating mechanism connects in the guide rail that opens and shuts. Above -mentioned clamping device, actuating mechanism can drive guide rail along self the length direction removal of opening and shutting to can be two leading wheels with the sport conversion of guide rail along self length direction that open and shut and draw close each other or keep away from along the range upon range of direction of the guide rail that opens and shuts, and then drive the voussoir guide holder and be close to or keep away from, finally drive the voussoir chuck and draw close or keep away from with the centre gripping each other or release the work piece.