An electric power tool includes a planetary gear reduction mechanism, a switch mechanism, an impact mechanism, a hammer mechanism, a torque fixing mechanism, and a torque adjusting mechanism. The switch mechanism includes a driving member, a first driven member, and a second driven member. A switching member is provided on the electric power tool and connected to the driving member to move it, and the driving member may drive the first driven member and the second driven member respectively to start or shut the impact mechanism and the hammer mechanism.