PURPOSE: To remarkably reduce the cost of wiring to each sub disaster prevention center from the central disaster prevention center and to provide the urgent broadcasting system capable of performing broadcasting from each sub disaster prevention center without trouble even when the fault of amplifying means, etc., of the central disaster prevention center takes place.

CONSTITUTION: When the broadcasting system of the building A is specified from a broadcasting system communication line specification means 101B of a central disaster prevention center 1, a data signal specifying the broadcasting system and a voice signal for remote micorphone are sent through a signal transmission means 103 to a CATV coaxial cable 30. A connection means 203 of a sub disaster prevention center 2 connects to the corresponding communication line based on the data signal and the voice signal is amplified and sent by an amplifying means 202. When the broadcasting system of the building A is specified by it own management building broadcasting system specification means of the sub center 2, the voice signal of the remote microphone of the center 2 is amplified and transmitted by the means 202.