PURPOSE: To prevent mutual interference between adjacent locking spring parts by providing rigidity reinforcing means in base parts of bends of locking spring parts.

CONSTITUTION: After a terminal spring 11 is stored in a housing, a metal fitting 4 is put on the upper face of a spring plate 5, and a screw is inserted to a tapped hole 9a to fix the metal fitting 4 and the spring plate 5 to a fire sensor base. When an electric wire is inserted between a terminal metal fitting 7 and a terminal spring 11, a locking spring part 13 and a pressing spring part 14 are bent and displaced by the pressing force of the electric wire. At this time, the deforming force of one locking spring part 13 is not transmitted to the other locking spring part 13 through a bottom part 12 because the locking spring part 13 is provided with a rigidity reinforcing means 20 in a bend base part 15. Therefore, the pressing force of the other locking spring part 13 to the electric wire is not affected by insertion of the electric wire to one locking spring part 13 because the pair of locking spring parts 13 are free from mutual interference.