Self-locking screwdriver

The invention discloses a self-locking screwdriver, belongs to the technical field of hardware tools, and aims to overcome the defect that an existing screwdriver head is instable in installation. The screwdriver comprises a screwdriver handle and a screwdriver head, a movable operating part is arranged on the screwdriver handle, a limiting part is arranged on the operating part, a limiting groove is formed in the screwdriver head, and a first elastic part is arranged between the operating part and the screwdriver handle so that the limiting part can be embedded into the limiting groove. The tool bit can be stably installed on the tool handle through the cooperation of the limiting part on the operation part of the tool handle and the limiting groove in the tool bit, the elastic part is arranged between the operation part and the tool handle, and the limiting part can automatically return to be embedded into the limiting groove under the action of the elastic part, so that the installation operation of the to