To make a transaction smooth by unnecessitating the confirmation of the nationality or using currency of a customer in the transaction dealing with the plural kinds of currency.

This processor is provided with plural sub-total keys 4c for each of plural kinds of currency, and a sales total sum based on inputted merchandise information is calculated by a currency unit corresponding to the pressed sub-total key 4c, and this is displayed on a display. Thus, an operation for deciding a currency unit being the basis of the calculation of the sales total sum and the display of it on the display is operated in the timing of the pressing of the sub-total key 4c after the recognition of the currency to be used by a customer by a cashier. Thus, the transaction can be smoothed without applying a load for allowing the cashier or an operator to confirm the nationality or the using currency of the customer. Moreover, the sub-total key 4c is provided with a function for designating the currency so that it is not necessary to separately designate the currency and press the sub-total key 4c, and the operation can be simplified.