A period required for a time-consuming cross-contamination test is cut down or omitted, and a burden imposed on the customer by the costs of samples, reagents, etc. used in the test are reduced. A data failure caused by cross-contamination can be efficiently prevented. A maintenance service office establishes a connection via a communication line between a computer installed in the maintenance service office for maintenance of automatic analyzers and a customer's automatic analyzer or a personal computer placed in a customer's facility. The maintenance service office receives information regarding cross-contamination from reagent manufacturers and other customers (such as clinical examination rooms or centers) and validates it. The validated information is transmitted from the maintenance service office to the customer's automatic analyzer or personal computer via the communication line.