The invention discloses a walnut cracker and belongs to daily necessities. The walnut cracker comprises a semi-circular support, a slotted screwdriver and clamping ends, wherein the slotted screwdriver is inserted into the top of the support, and the clamping ends are arranged at two bottom ends of the support. The slotted screwdriver, inserted from the upper bottom center of the support, is capable of moving along the center axis of the support and rotating within a plane perpendicular to the center axis of the support. The clamping ends are inserted into through holes which are formed in the sidewalls of the support symmetrically, the section of each clamping end along the axis is in the shape of I, needle-shaped projections are formed on the inner surfaces of the clamping ends, and a compressed spring is arranged between the middle of each 'I'-shaped structure and the corresponding outer wall of the support. The walnut cracker has the advantages that a user can extend the slotted screwdriver out downwardly, insert the same into a crack of a walnut shell, drop the support down and then exert force on the clamping ends to fix a walnut so as to break the walnut shell by turning the slotted screwdriver; a mode of breaking the walnut shell from inside to outside can protect walnut kernels from being squeezed, so that walnut kernel breakage can be avoided effectively.