An electric ratchet wrench as one example of the ratchet wrench includes an electric motor, a holder that rotatably holds a socket via a one-way clutch mechanism, and a spindle configured to convert a driving force from the motor into a reciprocating rotation motion of the holder. A space is provided between the socket and the holder. The space includes large interval portions and small interval portions. The small interval portions are adjacent to the large interval portions in a rotation direction (lock direction) of the socket and have distances smaller than distances of the large interval portions. Additionally, the one-way clutch mechanism includes columnar locking pins disposed between the spaces and have a diameter with a size equal to or less than the distances of the large interval portions and exceeding the distances of the small interval portions.