PURPOSE: To discriminate the necessary or unnecessary of encipherment and to prevent the occurrence of erroneous operation by providing a enciphering and decoding means for a transmission data and a means controlling the encipherment by an identification code of a transmission opposite party on the facsimile equipment.

CONSTITUTION: An identification code read means 120 reads an identification code of as transmission opposite party. An encipherment control means 130 receives an identification code of a transmission opposite party from the identification code read means 120 and used an identification code table storage means 140 to confirm the identification code of the transmission opposite party and does not start an enciphering means 150 when the code is not registered. When the identification code is registered, the encipherment control means 130 acquires an encipherment algorithm corresponding to the identification of the transmission opposite party. Then the encipherment control means 130 starts the enciphering means 150 so as to be operated on the acquired encipherment algorithm. Thus, the discrimination circuit of the necessary or unnecessary of the encipherment due to a difference from the transmission opposite party and its operation are automated and occurrence of erroneous operation is prevented.