The LC filter includes a first AC reactor having a first core and a first coil whose terminal is connected to an AC power source, a second AC reactor having a second core and a second coil whose terminal is connected to a power convertor which converts AC to DC, a capacitor, a casing to house these components, a cooling air introduction portion which introduces cooling air into the casing, and a cooling air discharge portion which discharges the cooling air from the casing in a predetermined direction. The second AC reactor is positioned so as to provide a second gap between the outer periphery of the second coil and the casing, and so that the axial direction of the second coil coincides with the flow direction of the cooling air flowing along the second gap.