To miniaturize parts in use as a whole and simplify a slider guide as well, while allowing assembling and disassembling a punch and a guide bush by improving the fixing device.

This apparatus, which is used for fixing the punch 6 or the like to make notches from the peripheral wall of the hollow body formed in the deformation apparatus 1 by the internal high pressure plastic deformation process, comprises the punch that is guided by the guide bush 5 received by the slider guide 4 arranged in a deformation tool 1, 2, the guide bush 5 affixed to tool 1, 2 by a clamping device, which uses the fluid pressure from its source or fastening force of screws 8, and the slider guide 4 is held by the same clamping action.