To provide an inverter device, wherein there exists a large difference between a voltage of positive polarity and a voltage of negative polarity, an output of a steep pulse waveform is easily obtained, its waveform and period are easily adjusted, and low pricing is attained, even if it is reduced by one switching device.

An inverter circuit IN is constituted, in such a manner as first to third three IGBTs (B1 to B3) are bridge-connected in the shape of (h). A control circuit CN applies gate signals of pulse widths which are reverse to each other, periodically separated by dead times, to the first IGBT (B1) among these three IGBTs; while the control circuit simultaneously applies the gate signals of the same pulse widths to the second and the third two IGBTs (B2, B3), of which the arms are different regarding each of them, and moreover, a gate signal of the identical pulse width of the second and third two IGBTs (B2, B3) is applied simultaneously.