A printer comprises a card reader and a data writing unit. The card reader reads out an image stored in a memory card. The data writing unit writes the image, which is read out by the card reader, in a flexible disk to store this image. The printer is adapted to be controlled under a simultaneous print mode for simultaneously performing both of printing and storing the image. When an instruction for printing is given to the printer under the simultaneous print mode, printing the image on a recording paper is carried out. At the same time, storing the image in the flexible disk is simultaneously carried out.