A pawl mechanism of a ratchet wrench, including a wrench main body, a pawl, a ratchet wheel and a shift member. Four engaging recesses are formed on a bottom of a first recess of the wrench main body. A first engaging channel and a second engaging channel are respectively formed on two sides of the pawl corresponding to two of the four engaging recesses of the wrench main body. A spring and a steel ball are disposed in each of the engaging channels, whereby the steel balls can be located in the corresponding engaging recesses of the wrench main body.