A switching power-supply device configured to convert and output a first direct voltage supplied to a second direct voltage by alternately turning on and off a first switching element and a second switching element includes: an inductor; a detection unit; a reference voltage generation unit; a comparison unit; a driving unit; a driving signal generation unit; and a power supply circuit, the driving unit turns on the first switching element during a period where the driving signal is supplied, the reference voltage generation unit comprises: a capacitor; a superimposing unit; a charging-and-discharging unit; and a first charging current control unit, and the first charging current control unit charges the capacitor with the first charging current until regeneration of the inductor is completed and charges the capacitor with the second charging current after the regeneration of the inductor is completed until the driving signal is outputted.