Failure diagnosis system

A failure diagnosis system, comprising:

• a plurality of sensors of the same type that are disposed under the same environments;
• an operating condition detection part that detects an operating condition of a device to be detected;
• a plurality of sensitivity adjustment parts that are disposed in correspondence with the plurality of sensors, and adjust receiver sensitivities of sensor signals output from the plurality of sensors based on the detected operating condition to output adjusted sensor signals;
• and
• a failure diagnosis part that diagnoses whether or not the plurality of sensitivity adjustment parts are in failure,
• wherein the failure diagnosis part detects a failure condition of a sensitivity adjustment part to be diagnosed when a difference between a comparison value calculated based on a maximum value of the adjusted sensor signals output from the plurality of sensitivity adjustment parts at a given interval, and a maximum value of the adjusted sensor signal output from the sensitivity adjustment part to be diagnosed at the given interval is larger than a given amount.