Abstract: An automatic control method for a taphole opener for opening a taphole by giving impact and rotation to a drill unit holding a drilling rod and driving the drill unit forward and backward by a hydraulically driven feed motor, which method comprises the steps of; detecting the driving load in the form of detected hydraulic pressure, stopping the driving but maintaining the rotation when said detected pressure reaches an upper limit set value beyond which buckling may occur, and resuming the driving when said detected pressure falls to a lower limit set value or below. The drilling rod of the drills unit is prevented from buckling and idle hitting and a quicker taphole opening operation and enhanced accuracy of taphole depth can be obtained. Thus remote operation is made possible through the automation of the taphole opening work.