PURPOSE: To provide a multicolor printer having multiple function and easy to use wherein color deviation does not occur in the case that the color deviation is severely inhibited such as in LOGO mark or ruled line of forms, while a three-primary color mode can be selectively used in the case that some color deviations are allowed.

CONSTITUTION: As a color developing machine set, 2 types of color developing machine sets (a three primary color developing machine set 4 and a special color developing machine set 4') for the three colors and special color (toner of a desired color made by using dye and pigment specific to the color without coloring by color registration of the three primary colors) are provided in an exchangeable way. Also, a mechanism control circuit 10 for printing with color by switching the three primary color mode and the special color mode is provided.