To correct precisely the image writing position and thus form high qualified composite images with no image dislocation and color dislocation by controlling the image writing position relative to the recording medium of image information inputted at more limited distances than the minimum distances of image elements.

A synchronizing signal delay controller 25A to be an image writing position correction circuit of a major scanning direction is set within a major scanning synchronizing dividing circuit 25. If the data value of a 4-bit dip switch 37 is one except F, the initiation timing of an image clock is variable in the range of from the input period of a BD synchronizing signal to a first primitive clock (finer clock than image one) through fifteenth one. Also, the set width can be done with fineness eight times the image clock. Accordingly, since an image clock one cycle is set to be the width of one image dot, the image writing position in the major scanning direction comes to be control corrected at the width of one-eighth of one dot relative to the BD synchronizing signal.