A switching element driving device includes: a drive circuit that is connected between an element driving power supply and a circuit ground and outputs a driving signal to a driving switching element; a capacitor that is connected between the circuit ground and a reference ground to which a potential reference side conduction terminal of the driving switching element is connected; and a regulator that charges and discharges so that the capacitor has a predetermined terminal voltage. The regulator discharges the capacitor when the terminal voltage exceeds an upper limit value, and charges the capacitor when the terminal voltage falls below a lower limit value.