a converter that converts AC power supplied from a side of an AC power source into DC power;

a smoothing capacitor provided in a DC link on a DC side of the converter;

an inverter that performs mutual power conversion between the DC power in the DC link and AC power that is driving power or regenerative power of a motor;

a capacitor capacity measurement unit that measures a capacity of the smoothing capacitor, on the basis of the DC voltage applied to the smoothing capacitor at a point after an initial charging operation is complete;

a data record unit that records a plurality of pieces of data composed of a measurement value of the capacity of the smoothing capacitor measured by the capacitor capacity measurement unit and a date or both a date and time when the measurement has been performed;

a deterioration characteristic calculation unit that calculates a deterioration characteristic line indicating a change of the capacity of the smoothing capacitor with respect to elapsed time, on the basis of the plurality of pieces of data recorded in the data record unit; and

a life prediction unit that predicts a period when a life of the smoothing capacitor ends, on the basis of the deterioration characteristic line calculated by the deterioration characteristic calculation unit.