The text messaging system consists of mobile terminal (5) connected to mobile communication network (4), information terminal (3) connected to computer network (2), and server (1) connected to the mobile communication network and the computer network. The information terminal (3) has status detection means (22), (23), and (24), and detects an operational status including at least the connection status of the computer network and notifies the server (1) of it. The server (1) has status administration means (8) and (9) and decision means (10). The status administration means (8) and (9) retain the operational status of the information terminal (3) notified from status detection means (24) for each user. The decision means (10) determines a send mode according to the operational status of the information terminal such as whether to send a text message to an information terminal or to send a text message with a network application.