A wrench comprises a handle and a head extending from the handle. A peripheral wall defining a hole in the head includes a compartment. An annular groove is defined in an end of the peripheral wall defining the hole. The annular groove is partially coincident with the compartment. A pawl is slidably received in the compartment and biased to engage with a gear wheel in the hole. A switching member is partially mounted in the hole for moving the pawl when switching of the ratcheting direction is required. A retainer ring is partially engaged in an annular groove in the switching member and partially engaged in the annular groove of the head. The retainer ring is retained in place by a wall defining the compartment. The switching member is not moved when the pawl moves as a result of free rotation of the wrench.