A thermal head driving integrated circuit may be used to perform an “n” color or “n” gradation printing operation with a simplified circuit having a reduced size by employing a single delay element connected to a plurality of resistive heating elements. The integrated circuit has a plurality of drive units each for driving a respective one of the heating elements and each having a drive transistor for driving a respective heating element, one or more delay elements, the number of delay elements being less than “n”, for supplying delayed print data to the drive transistor, a print data storing unit for storing the print data of each of the “n” types, and a print data supplying unit for supplying print data stored in the print data storing unit to the “n” delay elements.