The discharge control device for a power conversion system performs discharge control to discharge a capacitor parallel-connected to the input side of the power conversion system including a plurality of pairs of high-side and low-side switching elements connected in series and each controlled by a drive unit, by turning on the high-side and low-side switching elements of one of the pairs at the same time. At this time, the discharge control device inhibits an ON command from being inputted to the drive units for the high-side and low side switching elements of the other pairs.