Discharge circuit for smoothing capacitor of DC power supply

A discharge circuit for a DC power supply smoothing capacitor 326 that is used in a power conversion device 200 that supplies DC power via a switch to the DC power supply smoothing capacitor 326 and an inverter 144, includes; a resistor 324 that discharges charge in the capacitor 326; a switch 325 connected in series with the resistor 324, that either passes or intercepts discharge current flowing from the capacitor 326 to the resistor 324; a measurement circuit 317, 319 that measures a terminal voltage of the capacitor 326; and a control circuit 172 that controls continuity and discontinuity of the switch 325; wherein the control circuit 172, after having made the switch 325 continuous and starting discharge of the capacitor 326 by the resistor 324, if a terminal voltage of the capacitor 326 as measured by the measurement circuit 317, 319 exceeds a voltage decrease characteristic set in advance, makes the switch 325 discontinuous and stops discharge by the resistor 324.