An optical scanning device comprises: an oscillating mirror which has a pair of electrodes and a mirror oscillator; a driving unit which applies a wave-like driving signal to the electrodes so as to oscillate the mirror oscillator correspondingly to the driving signal; a detecting unit which detects an oscillation amplitude of the oscillating mirror; an adjusting unit which changes a value of at least one of a duty ratio, a driving frequency, an amplitude, and a bias voltage of the driving signal as a parameter so as to adjust the oscillation amplitude detected by the detecting unit to a target value; and a storing unit which stores the value of the parameter changed by the adjusting unit as a reference value, wherein when the oscillating mirror is activated, the adjusting unit starts the adjusting of the oscillation amplitude with using the driving signal based on the reference value.