To improve the reliability of automatic light volume control by shortening the continuous lighting time of a light emitting element for early automatic light volume control.

The optical scanning device is equipped with a plurality of light emitting elements (LD1 and LD2); an optical scanner (34); a sensor (38 mc, 65) for detecting a standard point for optical scanning; a sequencer which generates automatic control prompting signals (sB, sG, sC and sH) destined for each light emitting element by initiating a signal generation sequence in response to a start signal (sA); and a plurality of automatic control means (PDm, APC1 and APC2) for automatically controlling the light volume of each light emitting element to a preset value in response to each automatic control prompting signal (sB, sG, sC and sH). In this device, the sequencer includes an early prompting signal generation means (Iapc) which generates the automatic control prompting signal (sB) destined for one light emitting element in response to the start signal (sA) and stops the automatic control prompting signal (sB), when a first count value reaches a first preset value (Dt1) after the start of the first count of a clock and later, repeats the generation of a prompting signal which generates the automatic control prompting signal (sC) destined for the other light emitting elements by the number of these elements.