To provide a line controller with which a caller number notice service is served by using a terminal adaptor, having no provision for an existing caller number notice service.

This line controller 1 is provided with caller telephone number data detection means 12, 13, that detect caller telephone number data outputted from a terminal adaptor having no provision for a caller number notice service, a D/A converter means 17 that converts the detected caller telephone number data into an analog signal, a changeover means 20 that outputs an analog signal outputted from the terminal adaptor or the converted analog signal into an analog telephone line, and a changeover control means 13 that outputs the converted analog signal to the analog telephone line, by controlling the changeover means 20 when the caller telephone number data are detected.