To clear transfer of a signal between security devices in a house and at the side of a centralized monitor and to specify/judge a floor and a room as the source of a fire by a dweller of the house when the fire, etc., occurs.

When the fire is sensed by fire sensors 1a, 5a installed in each of the houses Al, A2, occurrence of the fire is unformed by producing a voice message by the security devices 3a, 7a in the houses via repeaters 2a, 6a, notifying fire confirmation signals f1, f3 to centralized monitoring security devices 4a connected with the security devices in the houses, notifying fire linked signals f2, f4 to the security devices in the houses of each of the houses at the floor where the fire occurs except the house where the fire occurs or its immediate upper floor and informing the voice message that the fire occurs in the neighborhood by the centralized monitoring security devices to be connected with the security device in the houses.