thermal chamber 1 changes thereby the effect switch 2 turns outwards since the inner pressure increases therefore the effect switch 2 can be driven by the heat condition of the thermal chamber 1 referring to fig4 and 6 an alarm device 9 driven by the above thermal effect switch 1 is shown the alarm device 9 includes a component unit 3 and an alarm unit 4 the component unit 3 is used to receiving the effect switch 2 of the thermal effect switch 1 the component unit 3 includes a top plate 33 and a sidewall 31 surrounding the top plate 33 a movable plate 32 is arranged under the top plate 33 and in a space defined by the sidewall 31 the movable plate 32 includes a flat plate 321 and an electric conductive protrusion 322 the flat plate 321 is arranged at the fringe of the effect switch 2 the alarm device 9 further includes two electrical conductive columns 5 perpendicular to the top plate 33 and passing through the top plate 33 each electrical conductive column 5 has a conductive portion 331 arranged at the bottom thereof the alarm unit 4 is arranged on the component unit 3 and includes a number of clapboards 41 the two electrical conductive columns 5 pass through the number of clapboards 41 the alarm unit 4 further includes a power supply 6 and an alarm 7 arranged on the clapboards 41 the power supply 6 may be a battery and the alarm 7 may be a light emitting element such as light bulb or light emitting diode the alarm 7 also may be a sound element such as trumpet or buzzer the alarm 7 may be also a shake element with a shake function the alarm.