To provide an adjustment system for shortening the time required for adjustment of merchandise purchase, especially adjustment time in credit card payment.

The adjustment system is provided with a merchandise identification means where merchandise information is recorded, a customer identification means where customer information is recorded, a portable information terminal reading and storing the merchandise information recorded in the merchandise identification means every time merchandise is put into a shopping basket and calculating the total of a purchase money amount, and an adjuster for reading the merchandise information stored in the portable information terminal and performing an adjustment processing. The total of the purchase money amount is calculated by a customer himself/herself, a payment method is selected, and in the case of the credit card payment, credit confirmation and content confirmation are performed by using electronic mail of a portable telephone.