A service proxy processing method is used with a network service system in which a service providing device connected over a network for performing predetermined capability processing can communicate with a plurality of client devices for performing network connection capability processing for recognizing connection status of each service providing device over a network. Each service providing device has a proxy process step of specifying a specific communications capability in response to a communications capability request from any client device when a predetermined service providing process is not performed in a predetermined period, allowing any service providing device in a network to perform as a proxy a communications process based on the specified specific communications capabilities, and making a transition to a network sleep status not recognized by a client device in the network.