A ratchet wrench includes a head and a handle. The head is assembled with a switch member and an active mechanism which provides a ratchet function. The switch member is switched to selectively engage the active mechanism, so that the active mechanism may be fixed or be rotatable to achieve the ratchet function. Therefore, the wrench is provided with the function of ratchet which makes the wrench easy to use and with the function of fixing which makes the structure strength of the wrench strengthened. Conveniency of using wrench is improved.