PURPOSE: To obtain a beautiful desired color-printed face free of color shift by providing a color sensor to recognize the colors in given places of a transfer paper to be used when thermal transfer printing is made to the thermal head.

CONSTITUTION: A serial thermal head 11 is made up by providing a color sensor 13 consisting of photo diodes where color filters to permeate only red color for example are deposited on the light receiving face on the extended line of the first row of a heating resistor 12 for example. When thermal transfer printing is made, the serial thermal head 11 is moved in the direction of crossing the printing direction of arrow by means of the head sending mechanism 23. Since, in the head 11, the line 17a of red heat-meltable ink is always detected by the sensor 13 for regulating the positions, clear-cut pictures free of position shift can be obtained.