To provide a sensor light with various uses aimed at by enabling it to operate with an external sensor other than a human body detecting sensor incorporated in it, and to make an effective use of lighting and alarm as its intrinsic functions.

The sensor is provided with a lighting tool 2, an alarm unit 6 generating an alarm tone, a human body detecting sensor 3 for detecting a human body, and a control part 100 operating by detection signals from the human body detecting sensor 3 to light up the lighting tool 2 and have the alarm unit generate an alarm tone among others. It is also provided with an input circuit 12 by an external sensor 11 apart from the human body detecting sensor 3, and the external sensor input circuit 12 inputs change of outputs of the external sensor 11 into the control part 100, which 100 determines that an abnormality takes place when the change of the inputted outputs exceeds a preset rate of change and lights up the lighting tool 2 or generate an alarm tone by the alarm unit 6.