A high strength wrench includes a head portion, a shaft and a handle. A length of the shaft is multiple times of a length of the handle. At least one slot extends along a longitudinal direction of the shaft and is formed at a circumferential surface of the shaft. A cross section shape of the shaft has a structural profile of an outer side with a relatively greater thickness and an inner portion of a relatively smaller thickness. Accordingly, the shaft has a greater structural strength to allow the wrench to bear operations of high torque.