PURPOSE: To provide a die-clamping device which is simply constituted and compact in size.

CONSTITUTION: A tie-rod 5 is projectingly provided to a fixed base 1 so that a movable base 3 may be movingly guided, and in this tie-rod 5, an engagement groove 5a for screws or the like is provided to the outer circumferential surface of a part projecting from the moving base 3 to the side of a counter fixed base in the condition where dies 2, 4 are closed. A locking member 12 of split die shape which is locked to/released from the tie-rod 5 through this engagement groove 5a is slidably provided in the axial direction of the tie-rod, while the moving base 3 is constituted in the upper and the lower stages 3a, 3b, and a die clamping cylinder 19 is interposed in the center part of these 3a, 3b between the vertically two-staged moving bases 3a, 3b. Thus, only one set of the die-clamping cylinder and an accessory hydraulic equipment may be sufficient, leading to a simple and compact constitution. The die-clamping cylinder presses the die directly by pressing down the center part of the downward- moving table, and even when the moving base is bent, this bending does not affect the die, preventing adverse effects to products.