A format conversion decision definition generating unit 104 stores information whether or not a response message format from a service unit 134 may be utilized in all later service callings of a business process without format conversion in a repository 121 as format conversion decision information 127, by referring to business process definition information 105 and adapter definition information 106. Then, when a business process operation control unit 132 executes the business process, an adapter operation control unit 133 refers to the format conversion decision information 127 about a target service 134 at the time, and skips the format conversion when information indicating that the format conversion is unnecessary is stored in the format conversion decision information 127.