FIRE ALARM SYSTEM

PROBLEM TO BE SOLVED: To easily construct a crime prevention system by utilizing the line of a fire alarm system. SOLUTION: In this fire alarm system 10 which is provided with a fire detector, a regional line to which the fire detector is connected, a regional bell, linking equipment 2 having a prescribed link relation with the fire detector, a transmitter P connected to the regional line and a dedicated transmitter line A and a fire receiver 11, if the fire detector detects a fire, the fire detector transmits a detector operation signal of a number V to the fire receiver 11, the transmitter P transmits a fire occurrence signal being a short-circuit signal via the regional line when operated and also transmits a transmitter operation signal via the transmitter line A, a crime prevention switch 1 is connected to the regional line, the crime prevention switch 1 transmits a crime prevention signal being a short-circuit signal to the fire receiver 11 via the regional line when operated, and when the fire receiver 11 receives the short-circuit signal, the fire receiver 11 makes all regional bells sound and also stops the link of the linking equipment 2 in the case the transmitter operation signal is not received.