In a service providing system, the problem of extensibility of applications may be overcome, and flexible cooperation is rendered possible between applications exploiting different protocols. An SIP environment and a Web environment are connected to a network. The SIP environment includes an SIP server, an SIP database, an SIP application server, an SIP application and a Web accessor component. The Web environment includes a Web server, a Web database, a Web application server, a Web application and an SIP accessor component. The management information is transmitted and received by cooperation management components, arranged in a Web accessor component and an SIP accessor component, respectively, in such a manner that the SIP environment and the Web environment cooperate with each other to provide services.