To provide a clamping device for presses and, in more detail, the clamping device for presses is constituted so that a cassette on which a die is placed attachably and detachably is positioned at and fixed to a bolster through a front clamp mechanism and a side clamp mechanism.

An upper cassette 18 is positioned at and fixed to an upper bolster 20 by the front clamp mechanism and the side clamp mechanism. The side clamp mechanism is provided with a side clamp member 44 which is movable nearer to and apart from the left side of the upper cassette 18 by reversibly energizing a side hydraulic cylinder. A projecting part 44a is projectingly provided so as to present on the extension in the vertical direction in the approximately middle part in back-and-forth directions on one side of the side clamp member 44. A recessed part 50 where the projecting part 44a is fit into and abutted on is formed so as to present on the extension in the vertical direction in the position corresponding to the projecting part 44a of the side clamp member 44 on the left side of the upper cassette 18. By fitting the projecting part 44a into the recessed part 50, the longitudinal shift of the upper cassette 18 is controlled.