This invention is directed to an image printing apparatus which can print images without any halfway offset or obverse/reverse pixel offset at a low cost. An image printing apparatus includes a clock generating section which generates a dot clock as the basis of each pixel forming an image, an image printing section which prints a one-line image in a main scanning direction in accordance with image data with reference to the dot clock output from the clock generating section, and prints a one-page image by repeating in the sub-scanning direction one-line image printing performed in the main scanning direction, and a clock control section which changeably controls the frequency of the dot clock during scanning of one line in the main scanning direction.