In a plate clamping device of a printing press for clamping a plate by a bottom clamping rail and a pressure plate, chips hardened to form serrations inclined in the lateral direction of a plate clamp so as to bite the plate in the direction of slipping-off of the plate are embedded in the clamp surfaces of the bottom clamping rail and the pressure plate such that the serrations on the bottom clamping rail side and the pressure plate side are inclined in opposite directions. Thus, the plate can be held with sufficient force without plastic deformation of the end of the plate, and the plate can be reused.