PURPOSE: To make a dot system printer possible to print easy readable and beautiful vertically written characters without requiring a complicated external circuit device by providing additionally a vertically written character pattern memory in parallel with a horizontally written character pattern memory so that they can be easily changed over for use.

CONSTITUTION: In parallel with a horizontally written character pattern memory 2, a vertically written character pattern memory 6 is added and both memories 2, 6 are connected to a 2 to 1 multiplexer 3 and a desired horizontally written and vertically written character pattern designated by a print character pattern instruction input signal 4 are selected by a vertical or horizontal selection signal 1 at the multiplexer 3 and sent to a printer 5. Consequently, the printer is capable of easily printing vertically written characters B in addition to the conventional horizontally written character printing A.