A driving device includes a driving circuit and a control circuit. The driving circuit has an input terminal and an output terminal and applies a driving voltage to a switching element through the output terminal. The control circuit outputs two types of control signals to the input terminal of the driving circuit. The driving circuit has a circuit group including multiple unit circuits which are turned ON by the same control signal. Each unit circuit includes one voltage source, one switch controlled to be turned ON and OFF by the control signals, and one resistor connected in series to the switch between the voltage source and the output terminal. Each voltage source outputs a different voltage, and each resistor has a different resistance. One end of each switch of all the unit circuits is connected to the output terminal.