1. A printer for printing image data inputted from a video apparatus, comprising: an image memory that saves inputted image data in order; printing means for printing the image data saved in the image memory; determination means for determining a kind of the inputted image data; and control means for controlling the image data saved in the image memory to be printed by the printing means according to a result of determining the image data by the determination means, wherein, if the determination means determines that the inputted image data is of a different kind from the previously inputted image data, the control means controls the image data previous to the image data whose kind is determined to be different by the determination means to be printed by the printing means.