A TCP transmission control device and a method of controlling a TCP transmission are provided that achieve greater efficiency of TCP transmission processes for applications that use intermittent transmission methods. A communication terminal includes a TSO control unit, which determines whether a TCP session open for data transmission is using a TCP segment link transmission process. The communication terminal also includes a link management unit, which manages all information consisting of the session identifiers employed in TCP sessions, and link transmission processing usage information and maximum number of TCP segment links notified from the TSO control unit, on a per TCP session basis.