A quick-return motion mechanism for use in an automatic magnetic drilling machine including a feed motor for generating power transferred through a worm wheel and a high-ratio reduction gear to a handle shaft to drive an electric drill. A one-way clutch is provided inside the worm wheel so that the handle shaft races on feed and is locked on return. The high-ration reduction gear is composed of elements which are arranged to cause the input and output sides of the high-ratio reduction gear to rotate in the same direction. The quick-return motion mechanism consists of an arrangement for restraining the input side element of the high-ratio reduction gear on feed and for releasing it on return to race the high-ratio reduction gear.