To provide a continuous paper electrophotographic apparatus in which the deviation of the position of beginning of writing image data on continuous paper is prevented and the accuracy of the position of beginning of writing is improved.

A VS signal which controls the beginning of writing image data in vertical direction with a laser beam is corrected to be synchronized with a BD signal which shows the beginning position of a horizontal scanning with the laser beam radiated on a photoreceptor drum, thus the phase difference between the BD signal and the VS signal is eliminated and the deviation of the position of beginning of writing image data on the continuous paper is prevented.