PURPOSE: To contrive to shorten production process and to reduce the hight of a device, while causing a mold clamping cylinder and a mold thickness regulating mechanisms to be separately assembled by equipping the mold clamping cylinder and a piston on the outer circumference of a tie bar, without arranging them on a stationary die plate and a tie bar.

CONSTITUTION: A mold clamping device is composed of following members, that is, the boost cylinder in which the tip of the piston rod stuck to a stationary die plate 13 is connected to a movable die plate 15, the tie bar 18 in which one end thereof is stuck to the stationary die plate 13 and the other end thereof passes through the movable die plate 1 and guides it, while equipping a spline from the other end, the piston 22 fitted on the outer circumference of the tie bar and a mold clamping cylinder 23 moving said piston, and further, two split lock nuts 24 engageable and detachable into the groove of the tie bar 18, a stopper 27 being fitted and slid onto the tie bar 18, and a rod causing a regulation collar 28 to be fitted thereon. Accordingly, as the tie bar is sufficient to be stuck to the die plate, the mold clamping cylinder is esaily assembled, and as a mold thickness regulating mechanism is equipped onto the mold clamping cylinder, the height of the device is reduced.