PURPOSE: To speedily stop an alarm started to sound from the outside in a sensor device with alarm.

CONSTITUTION: A main body case 11 is provided with two connection terminals 15 to which a connection wire 13 is connected. In the main body case 11, a detection part 17, a driving part 19, a sounding unit 21, and a reset part 23 are arranged. The detection part 17 which is connected to the connection terminals 15 detects a disconnection state wherein the connection wire 13 is disconnected and outputs a short detection signal to the driving part 19. The driving part 19 outputs a continuous driving signal to the sounding unit 21 on the basis of the detection signal. The reset part 23 receives a wirelssed indication signal and outputs a reset signal. The driving part 19 stops the driving signal with the reset signal.