PURPOSE: To enable a user to set a desired password code and to easily cope with even if the user can not remember the password code by enabling the password code to be rewritten by the generation of a specific signal in an error signal wherein a code which is inputted for the use of equipment does not match with the preset password code, and storing a code which is inputted in this state as a new password code.

CONSTITUTION: A recall switch 19 is operated to input a recall signal to a microcomputer 12 in the error state wherein the code inputted from a final control element 14 for the use of the equipment does not match with the password code UCD set previously in a nonvolatile memory 11. The microcomputer 12 enables the password code to be rewritten in response to the signal input and then stores a code which is inputted from the final control element 14 in this state as a new password code in the nonvolatile memory 11. Consequently, the user can sets his or her desired password code and copes with by easy repair even if forgetting the password code, and this system is advantageous in trouble and cost.