Abstract: An apparatus for boring a hole, which affords communication between a first member and a second member connected to the first member, in the first member, comprises cutting means hvaing a rotary axis, first drive means for shifting the cutting means along a first axis extending in the direction orghogonal to the rotary axis, second drive means for shifting the cutting means along a second axis orghogonal to the rotary axis and first axis, third drive means for rotating the cutting means about the rotary axis, detecting means for detecting a load acting on the cutting means and control means for controlling the first and second drive means to correct the position of the cutting means on the basis of a detecting signal provided from the detecting means so as to prevent an overload from acting on the cutting means.