A power conversion apparatus comprising: an inverter including a plurality of upper arms having switching elements of wide band gap semiconductors and a plurality of lower arms having switching elements of wide band gap semiconductors; a control unit that is configured to perform the following steps, when an excess current resulting from a short circuit flows through the inverter ; first turning off a first arm, which is the upper or lower arm disposed on a path of the short circuit through which the excess current flows, and then, after a dead time period, turning on a second arm that forms a half-bridge with the first arm, and at the end of a second time period that starts when turning on the second arm, turning off the second arm in accordance with a current flowing through the second arm, wherein no antiparallel reflux diodes are connected to an outside of the switching elements, and each of the switching elements is a vertical SiC-MOSFET, characterized in that the control unit is configured for synchronous rectification operation executed on a vertical SiC-MOSFET through whose body diode a reflux current is flowing, such that not only the body diode of the SiC-MOSFET but also a low resistant channel conduction of the SiC-MOSFET, which is connected to the body diode in parallel, is utilized as a current path for the reflux current, and the power conversion apparatus is configured such that during the second time period, a value and direction of a reflux current flowing through a switching element of the second arm is detected by a shunt resistor, and if the detected reflux current is smaller than a threshold value that is a level which does not cause bipolar degradation, said second time period ends and all phases of the upper and lower arms are cut off. an inverter including a plurality of upper arms having switching elements of wide band gap semiconductors and a plurality of lower arms having switching elements of wide band gap semiconductors; a control unit that is configured to perform the following steps, when an excess current resulting from a short circuit flows through the inverter ; first turning off a first arm, which is the upper or lower arm disposed on a path of the short circuit through which the excess current flows, and then, after a dead time period, turning on a second arm that forms a half-bridge with the first arm, and at the end of a second time period that starts when turning on the second arm, turning off the second arm in accordance with a current flowing through the second arm, wherein no antiparallel reflux diodes are connected to an outside of the switching elements, and each of the switching elements is a vertical SiC-MOSFET, characterized in that the control unit is configured for synchronous rectification operation executed on a vertical SiC-MOSFET through whose body diode a reflux current is flowing, such that not only the body diode of the SiC-MOSFET but also a low resistant channel conduction of the SiC-MOSFET, which is connected to the body diode in parallel, is utilized as a current path for the reflux current, and the power conversion apparatus is configured such that during the second time period, a value and direction of a reflux current flowing through a switching element of the second arm is detected by a shunt resistor, and if the detected reflux current is smaller than a threshold value that is a level which does not cause bipolar degradation, said second time period ends and all phases of the upper and lower arms are cut off. <EOS>