Abstract: An in-port capable of receiving a cartridge containing a plurality of thermal sheets of standardized size, a platen roller, and a thermal head are generally sequentially aligned in a direction. A thermal sheet picked up from the cartridge is turned at about 180 degrees along the platen roller, and fed out through an out-port arranged in the same side as the in-port. Thus, a very compact, front-in/front-out printer can be realized. Therefore, a card-size printer for the printing sheet of size B7, which can be inserted into a 3.5 inch-file bay, can be provided.