Provided is a syringe pressure generating and pressure displaying device applied to a syringe configured such that an auxiliary device is detachably attached to the cylinder flange while the rod bar is installed in the auxiliary device so as to pass therethrough, and a grip of the hand on a lever that is hinge-connected to the auxiliary device so as to be disposed horizontally in line with the syringe creates a rotational motion due to leverage, whereupon the rotational motion is converted into a linear motion via a motion-converting means, and the rod bar and the piston are moved with increased force.