Reflexive two-way fire detector

The application provides a reflexive two-way fire detector, comprising: a first circuit composed of normally-on terminals and a normally-on metal piece disposed between the normally-on terminals; a second circuit composed of normally-off terminals and a normally-off metal piece disposed between the normally-off terminals; and a metal detecting piece, abutting against the normally-on metal piece and the normally-off metal piece, and having a first state in which the first circuit is a normally-on circuit and the second circuit is a normally-off circuit under the non-heated state, and a second state in which the first circuit is an off circuit and the second circuit is an off circuit under the heated state. The reflexive two-way fire detector provided by the application can ensure differenton and off logic relationships generated with the metal pieces at both sides simultaneously by the metal detecting piece in the case of timely detection of the fire alarm, thereby avoiding false alarmgenerated by misoperation