FAILURE DETECTION DEVICE, FAILURE DETECTION METHOD, AND ELECTRIC POWER STEERING DEVICE

PROBLEM TO BE SOLVED: To provide a technique for identifying a faulty sensor from a plurality of sensors even when a failure in which a detection signal of a sensor rises or lowers from a normal value occurs.SOLUTION: A failure detection device includes a plurality of sensors for outputting an electric signal of a value according to twisting amount of a torsion bar connecting a first rotation axis and a second rotation axis when specific power supply voltage is supplied to detect a failure of a relative angle detection device for detecting a relative rotation angle between the first rotation axis and the second rotation axis. The failure detection device determines whether or not an output value when power supply voltage different from the specific power supply voltage is supplied to each of the plurality of sensors is within a preset specific range, and determines that a failure occurs in the sensor that is not in the specific range.