To provide a temperature-sensitive switch operable at a sufficiently high operation speed without being influenced by its mounting direction, targeted at a temperature-sensitive switch normally in an off-state and turned on by rise of the outside temperature.

A fusible alloy receiving electrode 2 is formed on one surface of an insulation substrate 1; a fusible alloy piece 6 is arranged in the middle of the electrode; respective lead conductors 41 and 42 are attached to both ends of the electrode 2; gaps g are formed between the respective conductor tip parts 410 (420) and the electrode ends 21 (22); the both sides 61 (62) of the fusible alloy piece are so arranged as to face the respective gaps g (g); and fluxes 51 (52) having a melting point equal to or lower than that of the fusible alloy piece 6 are interlaid in the respective gaps g (g).