Abstract: In a pen pressure device including a carriage, a pen axially movably supported to the carriage in such a manner that a front end of the pen is opposed to a paper, a pen pressure spring for biasing the pen toward the paper, a return spring for biasing the pen in a direction apart from the paper; the improvement comprises a hammer mounted on the carriage and adapted to be biased by the pen pressure spring having a spring force greater than that of the return spring to thereby urge the pen, and a cam member for moving the hammer to a retracted position where the pen is not urged by the hammer.