To provide a metal mold device by which respective blades of an expensive raw material can be inexpensively made when a cutting metal mold of a small work is installed in a metal mold holder.

A pressurizing device having a freely reciprocating ram 15 is arranged in a main body of a cutting work machine, and a moving blade holder 31 (a metal mold holder) in which a moving blade 135 is arranged so as to be freely inserted- extracted, is connected to the tip of the ram 15 of the pressurizing device, and a fixed blade holder (a metal mold holder) in which a fixed blade is arranged so as to be freely inserted extracted in order to cut a work by cooperating with the moving blade 135 is provided. A metal mold of the moving blade 135 and large and small fixed blades having the size corresponding to the size of various works and a spacer 39 having an installing object part corresponding to the size of the metal mold in order to install this metal mold, are combined with each other, and these combined spacer and metal mold are arranged in a metal mold holder so as to be replaceable. The spacer 39 is arranged by an inexpensive steel material, and the metal mold to cut a small work is made of an expensive raw material, but since it is formed in the size slightly larger than the size of the work, wastefulness is eliminated, and economical efficiency is attained.