A variable magnification electrostatic copying apparatus comprising a transparent plate on which to place a document to be copied, an optical system for projecting the image of the document onto an electrostatographic photosensitive member at any desired projecting ratio selected from a plurality of projecting ratios in an exposure zone located along the moving path of the photosensitive member, and a driving means for moving at least a part of the optical system and the transparent plate relative to each other. The optical system includes at least one position-variable optical element assembly adapted to be held at any of a plurality of positions corresponding to the aforesaid plurality of projecting ratios. The variable magnification electrostatic copying apparatus includes a unique improved means for varying the projecting ratio of the optical system by moving the position-variable optical element assembly.