A system that executes and manages the purchase of items at low cost is disclosed. This system, based on merchandising of one or more dealers, uses a merchandise assortment (MD) of each dealer specified by a customer's purchase control department for example as a customer specific electronic catalog. Then, this MD/electronic catalog stores for each item the information necessary for specifying its dealer and supplier. A server 10 is equipped with an item specific ordering controller 14 that, when it has received an order issuing request for ordering one ore plural number of items from a terminal of a user who belongs to the customer's purchasing unit, specifies a dealer who offers each item based on the MD information of each said purchasing unit. By this, it becomes possible for each user of the customer to make purchases based on the purchasing standard determined by the purchase control department by only specifying necessary items even without knowing the dealer names.