To improve the convenience of a customer and the security involved in discount merchandise purchase by eliminating the trouble of presenting a certification object (student identification card, resident card, etc., ) each time, the trouble of re-procedures involved in a change in personal information (entrance into school, employment, present address change, etc., ) and the possibility of trouble such as the rejection of applying a bargain price.

A control part 1 of an information processor of a credit company is provided with a personal information managing means 11 for registering/updating personal information recorded on a credit card periodically or each time change occurs, a determining means 12 for determining whether or not a customer is qualified to belong to a particular segment on the basis of the personal information recorded on the credit card with respect to the customer's purchase request for discount merchandise by using the credit card in a selling shop, and a settlement means 13 for performing credit settlement for the discount merchandise purchase when the determining means 12 determines that the customer is qualified.