Abstract: A wrench base structure comprises a positioning stage and an outward-spreading arm. The positioning stage and the outward-spreading arm are formed with positioning holes and restricting holes respectively. One end of the outward-spreading arm is connected to the positioning stage by an elastic section, and the elastic section keeps the outward-spreading arm being slanted outward at a predetermined angle. By such arrangements, the force of the outward-spreading arm returning the inclined outward-spreading angle is utilized to make the restricting holes stagger with the positioning holes of the positioning stage and position the wrench which is inserted through both the restricting hole and the positioning hole. Further, it can reduce the cost of production.