The present invention has an object to provide a server apparatus capable of accessing a terminal apparatus connected via an IP network to a router from an externally provided terminal apparatus in a simple and firm manner without previously performing complex setting operation.A server apparatus of the present invention is comprised of: a connection information transmitting unit, when specific information of a second terminal apparatus connected via a router to an IP (Internet Protocol) network is received from a first terminal apparatus connected via the IP network to the connection information transmitting unit, which transmits connection information to the first terminal apparatus, the connection information being employed so as to access the second terminal apparatus from the first terminal apparatus; and a relay unit, when the relay unit is accessed from the first terminal apparatus by employing the connection information transmitted by the connection information transmitting unit, which relays the first terminal apparatus to the second terminal apparatus having the specific information.