A ratchet wrench includes a handle and a head through which a hole is defined. A recess is defined in the inner periphery of the hole. A driving member is rotatably received in the hole. A pawl and a positioning member are respectively located in two respective ends of the recess. A spring is connected between the pawl and the positioning member. The pawl has a slot defined in a lateral side thereof so as to be connected to one end of the spring. The positioning member is a resilient member and has an engaging portion and a curved portion. An opening is defined between the engaging portion and the curved portion. The other end of the spring is engaged with the opening. The spring linearly biased between the pawl and the positioning member to engage the pawl with the driving member.