To provide a practicable chucking device capable of holding plural types of workpieces having considerably different diameters, providing superior cost performance, and reducing troubles in exchanging a workpiece for another different type of workpiece.

The chucking device 1 includes attachment soft jaws 3, 3 having a pillar-shaped support part 11 having a noncircular cross-sectional shape and a head 10 having a diameter larger than that of the support part 11, and bodies 2, 2 having a cross-sectional shape that is the same as the support part 11 in which three fitting grooves into which the support part 11 can be fitted are carved in the direction of a main shaft. By exchanging the attachment soft jaws 3, 3 or changing the fitting position or fitting direction of the attachment soft jaws 3, 3, the plural types of workpieces having considerably different diameters can be held.