Automatic withdrawing wrench for lathe chuck

The utility model discloses an automatic withdrawing wrench for a lathe chuck. The automatic withdrawing wrench comprises two half shells, two handles, four bolts, a square head, a spring and an X-shaped telescopic rod system. The two half shells are connected to form a cavity structure, the upper end of the square head in the cavity is connected with the X-shaped telescopic rod system, the other end of the X-shaped telescopic rod system extends out of the half shells, and the spring is hollowly sleeved at the lower end of the square head. An operator extrudes the X-shaped telescopic rod system protruding out of the half shell with fingers, the square head is pushed downwards to be exposed out of the half shell and compresses the spring, and at the moment, the square head can be inserted into the position of a chuck screw to loosen or fasten the chuck screw. After use, as long as the fingers leave the wrench, the square head retracts into the half shell under the action of the compression spring, so that the