To provide a workpiece gripping device which can minutely adjust gripping force thereof mainly for gripping a workpiece, to thereby prevent breakage or quality deterioration of the workpiece.

According to the structure of the workpiece gripping device, if a piston 54 makes contact with a movable claw 26, the piston 54 serves as a resistance when the workpiece W is gripped, and therefore the movable claw 26 is prevented from instantaneously moving to a fixed claw 18 due to an elastic force of an operating spring 44. Thus when the workpiece W is gripped by the fixed claw 18 and the movable claw 26, an impact force applied to the workpiece W can be eased. As a result, breakage of the workpiece W is prevented, and the gripping force for gripping the workpiece W can be minutely adjusted.