To provide a three-phase filter device which can suppress harmonic currents effectively by a relatively simple configuration.

The three-phase filter device 1 comprises a rectifier circuit 2 of a three-phase AC power supply 3, a reactor 6 connected with each phase of the rectifier circuit on the AC input side and a capacitor 7 connected between respective phases, a smoothing circuit composed of a DC side reactor 8 connected with the DC output side of the rectifier circuit and a smoothing capacitor 11, a switching element 12 connected between the smoothing circuit and the rectifier circuit, and a controller 13 controlling on/off of the switching element, wherein the controller controls on/off duty of the switching element such that harmonic currents contained in a current flowing to the AC input side of the rectifier circuit falls within a regulation value.