Abstract: A ratchet wrench includes a parts replacement structure that ensures effort-saved and smooth operation and prevents parts from getting lost. The wrench has a handle having an end forming a head portion that rotatably receives therein a driving collar. A lid plate is fixed to the head portion to retain a pawl member that engages and controls the rotation of the driving collar. The pawl member includes a pusher pad positioned on and movable along a top of the lid plate. A retention block is set at the side of the pawl member opposite to the driving collar to apply a biasing force to the pawl member through a push bar. In this arrangement, the push bar will not get lost when the pawl member disengages from and thus releases the driving collar for replacement.