A power conversion apparatus PWCS includes a smoothing capacitance element Cxp connected between a positive terminal and a negative terminal of a power source and configured to smooth a voltage change superimposed on a DC voltage, a switching circuit SWC converting the DC voltage into an AC voltage, a first bus bar BSB1 configured to electrically connect between the positive terminal of the power source and a terminal TCx1 of the smoothing capacitance element Cxp, a second bus bar BSB2 configured to electrically connect between the negative terminal of the power source and a terminal TCx2 of the smoothing capacitance element Cxp, and a filtering capacitance elements C1 and C2 electrically connected between the first bus bar BSB1 and the second bus bar BSB2. The first bus bar BSB1 and the second bus bar BSB2 include opposing portions and are disposed to allow the current to flow through the opposing portions in the same direction.