An optical scanning device comprising: a light source that emits a laser beam; and a driving unit connected to the light source and configured to drive the light source; the driving unit comprising: a first storage unit that stores in advance therein a setting value for controlling output of the laser beam; a second storage unit that stores temporally therein the setting value stored in the first storage unit; a storage controller connected to the first storage unit and the second storage unit; and a voltage detector connected to the storage controller and configured to detect a voltage value supplied to the driving unit, wherein the storage controller, upon the voltage detector detecting that the voltage supply is resumed, transfers the setting value stored in the first storage unit to the second storage unit automatically.