An apparatus for terminating and replaying transmission control protocol (TCP) communication between a server and cellular phone is disclosed. The TCP relay apparatus performs precise control for each TCP connection in the process of executing default TCP transmission control for the server and performing wireless-optimized TCP transmission control for the cell phone while facilitating setup for determination of the type of a network to which a communication destination terminal belongs. The TCP relay apparatus includes a unit capable of setting TCP control information suitable for the characteristics of a network linked to the destination device on a per-TCP connection basis, a unit which enables an application program to instruct the TCP control information setting, and a unit which determines the network type by judging whether the connection is a passive connection to a listen port or a TCP connection to the server.