Abstract: Clerk's processing means employed in the present invention has an input device for business data, a preprocess memory for storing the business data, and a clerk display device for displaying the business data and the results of decision about the validity of bank transaction. This clerk's processing means is operated by clerk and able to execute the preprocess as part of a series of transaction processes.Customer's processing means comprises an afterprocess memory for storing the business data and a guide display device for displaying the operating procedure for customer. This customer's processing means is operated by customer and able to execute the afterprocess as part of a series of bank transaction processes.And decision control means makes a decision about the validity of a bank transaction basing upon the business data stored in the preprocess memory, displays the results of this decision on the clerk display device, and also transfers the business data to the afterprocess memory.