PURPOSE: To obtain a color image forming device which is small-sized operates at a high speed and decreases color slippage by energizing two pieces of writing means successively and forming an image on sheet paper wound on a drum, thereby forming the image thereon.

CONSTITUTION: A copying machine 120 is constituted of a color image reader 121 and a color image printer 122. The machine is constituted that the 2nd writing means is energized with a prescribed time lag after the 1st writing means for forming the monochromatic color image is energized. Two kinds of the color images (for example, yellow and magenta images) are, therefore, successively formed first from the two writing means at the time of rotating a rotating members one turn, and the remaining color images (for example, cyan and black images) are formed by the next rotation at the time of forming the color image. The desired color image is thereby formed without considerably decreasing the image forming speed while satisfactory registration is maintained.