The object of the invention is to provide an inverter device and an electric motor device using the same to shorten a dead time. Thus, an inverter device is provided, which includes: a switching element including a control terminal and a pair of main terminals; a control circuit configured to output a control signal which indicates whether to instruct an ON state of the switching element; a decision circuit configured to output a decision signal which indicates a state of the switching element based on a voltage between the main terminals of the switching element; and a drive circuit configured to control the ON state or an OFF state of the switching element based on the control signal and the decision signal.