A failure detect device detects the presence of a failure in a peripheral member of a rotary shaft by analyzing a vibration generated in a device provided with the rotary shaft when the rotary shaft is rotated. A vibration detection unit detects the vibration of the device, and a rotation speed detection unit detects a rotation speed of the rotary shaft. An analysis unit calculates a frequency spectrum of the vibration of the device and determines an actually measured vibration level at each vibration order by dividing a frequency component of the calculated frequency spectrum by the rotation speed of the rotary shaft. A detection unit detects the presence of a failure in the peripheral member on the basis of the actually measured vibration level at each vibration order.