The invention provides a portable printer wherein provisions are made to prevent rain drops or dust particles from entering the interior of a body case through a paper exit port of the printer when a person carrying the portable printer in an exposed manner, for example, on his or her waist, is caught in rain or passes through a dusty area, and provisions are also made to ensure that power to the portable printer is turned off when not in use. More specifically, the invention provides a portable printer comprising: a body case having a paper storage section for storing paper; a storage cover swingably attached to the body case in order to open and close the paper storage section; a paper exit cover for opening and closing a paper exit port formed between the body case and the storage cover; and a control unit for controlling ON/OFF of power to the portable printer in conjunction with the opening and closing of the paper exit cover, wherein the control unit turns off power to the portable printer when the paper exit cover is set to close the paper exit port.