PURPOSE: To simply and radidly perform printing preparing work by performing the opening and closing of a gripper plate and the tensioning of a plate by a suspended fluid cylinder through the opening part provided to the bottom surface of a groove.

CONSTITUTION: In the plate vice device of a printing press, an opening part 21 is provided to the bottom surface of the groove of a plate cylinder 1 and fluid cylinders 24, 28, 29 clamping and tensioning a plate are suspended and fluid control valves 37, 38, 39 are connected to the cylinders and a pressure source is connected to the cylinders through the shaft 1a of the plate cylinder 1. A base plate 20 having almost the same shape as that of the bottom surface of the groove 2 of the plate cylinder 1 is provided to the groove 2 of the plate cylinder 1 in a freely detachable manner and, to the base plate 20, a plate vice stand, a gripper plate, the fluid control valves 37, 38, 39, the fluid cylinders 24, 28 opening and closing the gripper plate and the fluid cylinder 29 tensioning the plate are provided. Further, a switch controlling the operation of the fluid cylinder 29 clamping and tensioning the plate is provided in the vicinity of the plate vice stand and electric wirings controlling the fluid control valves 37, 38, 39 are introduced into the other shaft end 1b of the plate cylinder 1.