PURPOSE: To simplify construction, to restrict the object of approval and to prevent an illegal action by an operator and an approver by storing an approver's passward and the transaction number subject to an approval in an approval card and checking for the validity of the information of the approval card while comparing it with the preliminarily registered information by means of a host computer.

CONSTITUTION: A host computer 5 develops a received approved transaction execution telegraphic message in a telegraphic message development memory 6, retrieves a password information table 7 already set with the approver's name in the information of the approval card, checks whether or not the code number of the approval card coincides with that of the approver of registration and recognizes a valid approval action in the case of coincidence or interrupts the processing and informs a transaction execution terminal 1 of invalidity in the case of non-coincidence. It also checks the transaction number subject to the approval in the approved transaction execution telegraphic message against an approval waiting transaction number table 8 already set in the host computer 5 and executes the transactions in the case of coincidence or interrupts the transaction and informs the transaction execution terminal 1 of it in the case of non-coincidence. Thus, the construction can be simplified, the object of the aproval can be restricted and the illegal action by the operator and the approver can be prevented.