There are provided a switch driving device and a switch driving method capable of preventing a self-turn-on phenomenon. The switch driving device includes: a first signal output unit configured to output a pulsed first driving signal from a first output terminal thereof; a second signal output unit configured to output a pulsed second driving signal to a control terminal of a switching element from a second output terminal thereof; and a negative power supply generating unit configured to generate a negative voltage relative to a ground voltage and bias a low level of the second driving signal toward a negative side by the negative voltage. The negative power supply generating unit includes: a first capacitor configured to store charge by the first driving signal; and a second capacitor configured to generate the negative voltage across terminals thereof by the transfer of the charge from the first capacitor.
