Provided is a filter device to be connected between an AC power source (1) and a PWM converter (2), which includes a first AC reactor (3), a second AC reactor (4) that is connected between the PWM converter (2) and the first AC reactor (3), a filter capacitor (5) whose one end is connected to a connecting portion (9) between the first AC reactor (3) and the second AC reactor (4), and a housing (15) having a cooling air inlet (16) and a cooling air outlet (17) and containing the first AC reactor (3) and the second AC reactor (4), wherein the first AC reactor (3) is disposed upwind of the second AC reactor (4).