To perform color printing easily using monochromatic ink ribbons without causing any cost increase.

A pair of printer mechanisms 13 each having a thermal head 12 are arranged in parallel. A plurality of monochromatic ink ribbons 14 are arranged in parallel movably in the direction orthogonal to the direction for feeding a sheet P to the printer mechanism 13. Means for moving the monochromatic ink ribbon 14 is also provided. The ribbon moving means moves the monochromatic ink ribbons 14 sequentially and the thermal heads 12 of respective printer mechanisms 13 print the image of respective ink ribbons 14 on the sheet P while superposing.