The present invention allows for creating high quality images by coping with a variety of kinds of print mediums without having to prepare large-sized, large-capacity power supply and ink supply source. For this purpose, this invention detects the number of printing elements to be driven in a predetermined check area set in one scan area of the print head. If the detected value is greater than a predetermined threshold, either the number of printing elements to be driven in one scan period of the print head or one scan period from when the print head starts the printing scan until the next printing scan is started is selected and changed according to the set printing condition and the printing operation is performed accordingly.