The present invention whose object is to reduce compensation current at the time when suppressing harmonic distortion caused by harmonic voltage, to reduce capacitance of an inverter, a resonance suppression device configured to suppress resonance which occurs when a power facility such as a wind power generator is connected to a power system includes: an inverter configured to supply alternating current to the power system, the inverter being in parallel with the power facility; a current command value generation unit in which voltage at a connection point between the power facility and the power system is inputted thereto and a current command value is obtained by multiplying, by a transfer function, a harmonic component contained in the voltage at the connection point; and a current control unit configured to control the alternating current outputted from the inverter based on the current command value.