A printing apparatus includes: a main body having an accommodation part accommodating a printing medium; and an opening/closing cover supported by the main body so as to be swingable between a closed position and an opened position, a first unit and a second unit being selectively installable to the opening/closing cover, the first unit being configured to rotatably support a first platen roller, the second unit being configured to rotatably support a second platen roller, the opening/closing cover including a cover guide, the opening/closing cover having a discharge port discharging the guided printing medium. The first unit has a partition wall superposed to cover the cover guide and partitioning a space into the first platen roller-side and the discharge port-side in a case the first unit is installed to the opening/closing cover.