A hyperthermostable protease gene originating in Pyrococcus furiosus, in particular, a hyperthermostable protease gene which comprises the whole part of the amino acid sequence represented by the SEQ ID No.1 in the Sequence Listing and codes for the active portion of the protease; and a process for producing the protease by culturing a transformant prepared by using a plasmid having the above gene integrated thereinto.
