A power converter, comprising: an active converter that includes a semiconductor element, is adapted to be supplied with an AC voltage deliverable by an AC power source, and to rectify the AC voltage into a DC voltage, the active converter having a function of raising the DC voltage to a variable DC voltage level; a smoothing capacitor that is connected to an output side of the active converter and is adapted to smooth the DC voltage output from the active converter, the smoothing capacitor being connectable with a DC load at both ends thereof; a current limiting resistor that is connectable to the AC power source and connected to the active converter, and is adapted to limit a current flowing from the AC power source; a switching unit that is connected in parallel with the current limiting resistor; a DC voltage detecting unit for detecting a bus voltage that is a voltage across the smoothing capacitor; and a control device for controlling a voltage-raising operation of the DC voltage output from the active converter, wherein the control device is adapted to vary a reference voltage in accordance with the voltage raising level of the active converter, and to turn on the switching unit for bypassing the current limiting resistor in a case where the AC voltage is output from the AC power source, and turn off the switching unit in a case where a power failure occurs in the AC power source, and the control device is adapted to, before switching into a path on which the current limiting resistor is provided by allowing the control device to turn off the switching unit in the power failure, stop an operation of the DC load when it is determined that the bus voltage detected by the DC voltage detecting unit is equal to or less than said reference voltage. an active converter that includes a semiconductor element, is adapted to be supplied with an AC voltage deliverable by an AC power source, and to rectify the AC voltage into a DC voltage, the active converter having a function of raising the DC voltage to a variable DC voltage level; a smoothing capacitor that is connected to an output side of the active converter and is adapted to smooth the DC voltage output from the active converter, the smoothing capacitor being connectable with a DC load at both ends thereof; a current limiting resistor that is connectable to the AC power source and connected to the active converter, and is adapted to limit a current flowing from the AC power source; a switching unit that is connected in parallel with the current limiting resistor; a DC voltage detecting unit for detecting a bus voltage that is a voltage across the smoothing capacitor; and a control device for controlling a voltage-raising operation of the DC voltage output from the active converter, wherein the control device is adapted to vary a reference voltage in accordance with the voltage raising level of the active converter, and to turn on the switching unit for bypassing the current limiting resistor in a case where the AC voltage is output from the AC power source, and turn off the switching unit in a case where a power failure occurs in the AC power source, and the control device is adapted to, before switching into a path on which the current limiting resistor is provided by allowing the control device to turn off the switching unit in the power failure, stop an operation of the DC load when it is determined that the bus voltage detected by the DC voltage detecting unit is equal to or less than said reference voltage.