Abstract: A ceiling mounted fire detector comprises a detector 10 and a mount base 20 installed into a ceiling surface 1. The detector 10 includes a sensor unit 12 which, upon sensing a fire condition, produces an electrical signal to be transmitted to a control center through a signal line routed in the ceiling. The mount base 20 is provided in the form of a bottom-opened and top-closed barrel to receive therein the detector 10. Provided on the detector 10 is a pair of conductor prongs 15 by which the detector 10 is electrically and physically connected to the mount base 20. The mount base 20 includes a pair of sockets 23 for connection with the conductor prongs 15 and includes corresponding number of terminals 25 for wiring connection with the signal line for completing the electrical path from the detector 10 to the signal line.