Abstract: A constant pressure printing mechanism for use with a hand labeler: an actuating lever, pivotally connected to the frame of the hand labeler, is divided into a hand lever and a printing lever, which are pivotally connected to each other; a printing head is carried by the printing lever; a shock-absorbing tensioned spring is interposed between the hand lever and the printing lever to bias them to rotate toward each other and to rotate the printing head toward the platen; a retaining lever, pivotally attached on the hand lever, is engageable with the printing platen upon descent of the printing lever; before such engagement, the retaining lever retains the hand lever on the printing lever to move together; when the printing head moves to the platen, the retaining lever is raised away from the printing lever by its engagement with the printing platen; this enables the hand lever to further pivot slightly against the biasing force of the tension spring, even when the printing head abuts against the platen, so tha