PURPOSE: To quickly mount parts by fixing locking clamps to a plurality of T-shaped parallel grooves provided on the face to be machined of a bed plate via sliders and fixing parts to fixing clamps with the rotational movement of eccentric means.

CONSTITUTION: Sliders 3 are fitted to a plurality of sectionally T-shaped parallel grooves 5 provided in the face to be machined of a bed plate 1 and fixed thereto with fixing bolts 15 and locking clamps 16 with elastically deformable fingers 161-162 are supported along the grooves 5 to rotationally move an eccentric bed 17 so as to engage parts P to be machined with the fingers 161, 162. On the other hand, fixing clamps 2 are fixed to the other ends of the parallel grooves 5 with fixing bolts 11 to fasten and mount the parts P to be machined between each of the fingers 22, 23 and each of the fingers 161, 162 of the clamps 16. A workpiece is thus easily and quickly mounted with high reliability and damage to the parts after fastened is prevented.