An object of the present invention is to provide an electric power tool capable of automatically changing the rotating speed of an electric motor in accordance with operation conditions. The electric power tool 11 which carries out an operation of polishing, peel-off, cutting, or the like by swinging a tip tool 13 attached to a tool retaining 31 part within the range of predetermined angles by the drive power of the electric motor 12, wherein the electric power tool has a control device configured to indirectly detect the load of the tip tool from a current value, and to control the rotating speed of the electric motor 12 to a maximum rotating speed and a minimum rotating speed on the basis of the load of the tip tool 13.