In an inverter circuit configured with main circuit switches each having a control terminal and first and second main terminals through which the main current flows, and driving circuits each of which applies the driving voltage to the control terminal of each main circuit switch, and controls the main current in accordance with the voltage between the control terminal and the first main terminal, to switch the main circuit switch, between the main circuit switch and the driving circuit, noise-suppression circuits are provided, each of which is configured so as to detect fluctuations in the voltage between the first and the second main terminals of each main circuit switch, and, in accordance with the amplitude and the frequency of the detected voltage fluctuations, to bring to approximately zero the impedance across the control terminal and the first main terminal of each main circuit switch.