An electric drill apparatus having a low profile is provided which
comprises an annular cutter, a motor for rotating the annular cutter, a
rotary shaft assembly for rotating the annular cutter attached to its
leading end about a rotating, a rotation reduction mechanism disposed
between the motor and rotary shaft assembly for transmitting a driving
force of the motor to the annular cutter through the rotary shaft
assembly, a feed mechanism responsive to an operation of a manual handle,
for moving the rotary shaft assembly along with a straight line to
advance or retract the annular cutter attached to the rotary shaft
assembly with respect to a workpiece, and an adhesion base for securing
the electric drill apparatus to the workpiece. The annular cutter has a
plurality of cutting blades comprised of cemented carbide tips fixed on
its lower end, thereby it is capable of rotating at a high speed. The
rotary shaft assembly has a rotating shaft which rotates in a direction
different from that of a rotating shaft of the motor, thereby the drill
apparatus has a low profile.