A mold adjustment device of an injection molding machine is required for movement of a rear template that moves depending on a size of a mold in a toggle clamp of the injection molding machine. At this time, a spherical bearing and/or a bushing is attached to an outer circumference of a nut of a tie bar gear that rotates along a tie bar and a tie bar screw enduring a clamping force of the toggle clamp so as to be contacted with the rear template. This mold adjustment device clears up any factor generating vibration or noise during the injection molding, thereby remarkably decreasing stoppage generated during the mold adjustment process and also relatively reducing vibration and noise.