The electric motor car controller comprises a voltage detector (9) for detecting the voltage across a filter capacitor (4), an energy amount calculator (11) for calculating the amount of energy of the filter capacitor (4) from the output from the voltage detector (9), a band-frequency component detector (12) for extracting the given band-frequency component included in the amount of energy, a band-frequency component coefficient unit (13) for multiplying the band-frequency component by a given coefficient and outputting a q-axis current command correcting value, and a q-axis current command correcting value adder (17) for adding a q-axis current command correcting value to the q-axis current command value to correct the q-axis current command value.