PURPOSE: To save handling time for locating a fire sensor and to easily recognize its arrangement position at the time of periodically inspecting an automatic fire alarming equipment by providing a lighting device in the fire sensor and also providing a lighting switch for turning on the lighting device.

CONSTITUTION: The fire sensor 1 is constituted of a sensor fixing base 4 and a sensor external plate 5. A lamp 6 is incorporated in the internal part of the fire sensor 1. The lamp 6 is covered by the translucent sensor external plate 5 so that it becomes bright not only in the fire sensor 1 mainbody but also in its circumference. When the lamp lighting switch 9 of a receiver 2 is operated at the time of periodically inspecting the automatic fire alarming equipment, the lamp 6 of the fire sensor 1 in a guarding section, which is connected to a lamp power source line 3b, is turned on. In result, an obstacle in the circumference can be discriminated at the time of inspecting a machine room, a ceiling, etc., where ducts and layed pipes are intersected and the inspection work of the fire sensor 1 is smoothly executed.