Narrow-hole electric discharge machine

A narrow-hole electric discharge machine which performs electric-discharge machining on a workpiece by moving a narrow-hole electrode mounted on a spindle and a workpiece attached to a table relative to each other, the narrow-hole electric discharge machine comprising:

• a positioning guide which is attached to a guide arm below the spindle and in which a lower part of the narrow-hole electrode is inserted and supported so that the narrow-hole electrode can move in an axial direction, and
• a power supply element which is provided in a predetermined power supply position directly above the positioning guide of the guide arm and which directly contacts the narrow-hole electrode, which is movable in the axial direction, and supplies power thereto, wherein:
• the power supply element comprises a pair of power supply brushes having a large number of bristles composed of a flexible conductive material which is thinner than the pipe electrode,
• the power supply brushes are arranged symmetrically with respect to a central axis of the spindle so that each of the bristles extends in a transverse direction relative to the axial direction of the narrow-hole electrode, and the narrow-hole electrode inserted into the power supply element contacts the tips of the bristles, and
• a distance from the power supply position to a tip of the positioning guide, which is closest to the workpiece, is constant regardless of the length of the narrow-hole electrode.