To provide a currency transaction dealing system allowing a customer to order a transaction after confirming his dealing price in advance even in a market order and to update and confirm the fluctuation value of the exchange rate for his dealing price without re-inputting the transaction desire information.

This currency transaction dealing system is provided with a means displaying an order input screen on a customer terminal, a means displaying the current exchange rate as the transaction price when the transaction desire information is inputted, a means storing contract information as the materialization of the contract of the transaction when order information is inputted within a predetermined prescribed time, a means updating and displaying the current exchange rate as the dealing price when dealing price update information is inputted within the above time, and a means rejecting the acceptance of the order information and the dealing price update information after the above time elapses.