According to one embodiment, a communication server is provided with a communication interface unit, a storage unit, a setting unit and a roaming unit. The storage unit stores terminal list containing terminal ID and position ID (pID) of a content output terminal on a network. The setting unit transmits an instruction to set a session for outputting a content on the terminal, upon receiving from the terminal a first message containing user ID (uID), user position ID (upID) and content information associated with the session. The roaming unit selects, when a second message containing the uID and the upID is received, and it is determined that the user moved, a terminal having a pID corresponding to the upID, and transmits, to devices associated with session roaming to the selected terminal, an instruction to perform the session roaming.