PROBLEM TO BE SOLVED: To provide a failure determination device for a negative pressure operation device in which a failure determination of one of the negative pressure operation devices can be accurately executed in the case that a plurality of negative pressure operation devices are used under a condition of probability of occurrence of variation or lack of negative pressure.SOLUTION: A failure determination device 1 for determining a failure of a compressor and bypass valve 10 of a variable vane mechanism 9c acting as a negative pressure operation device and three valves 10, 14, 15 comprises an ECU 2. The ECU 2 determines whether or not a negative pressure is kept at a prescribed stable state in which the failure determination device can be stably operated on the basis of a vane opening degree αvn [step 23] and in the case that the negative pressure is kept at a prescribed stable state, a supercharger pressure PB detected when it is determined that the fixed state of the compressor and bypass valve 10 is
