The invention discloses a disk clamping device, relating to the technical field of semiconductor wafer techniques. The disk clamping device comprises a chuck main body, a cam, a rotating shaft and at least three clamping components, wherein the rotating shaft is installed on the chuck main body, has a common axial line with the chuck main body, and is used for driving the chuck main body to rotate; the cam is rotatably installed on the chuck main body, and has a common axial line with the chuck main body; the clamping components are installed on the chuck main body; the non-clamping end of each clamping component props against the movable surface of the cam through a limit stop block; the limit stop block is used for fixing the clamping component in the radial direction of the chuck main body when the cam rotates along with the chuck main body; and the movable surface is used for enabling the clamping components to move outward in the radial direction of the chuck main body when the cam rotates relative to the chuck main body. According to the invention, clamping of a disk is realized without damaging the clamped object, and the clamping position of the manipulator is not limited.