A ratchet wrench includes a head with a driving member located in a first room thereof. A clip is engaged with a first groove in the first room and a second groove in the driving member to retain the driving member in the first room. A pawl is received in a second room defined in the inside of the first room and engaged with the driving member. The pawl has a lip on the rear side thereof. A switching device is located in a third room communicating with the second room and outside of the wrench. The lip is inserted in a slot in the switching device. The switching device has a board which is rested on the lip and pushes either one of the two inclined faces of the recess in the rear side of the pawl to change the ratcheting engagement between the pawl and the driving member.