A small-hole electrical discharge machining device comprising: an electrode-for-machining being a stick-shaped electrode or a pipe-shaped electrode; an electrode guide for guiding a lower portion of the electrode in a Z axis direction through an interposed fluid layer of working fluid in the vicinity of a workpiece; a high pressure working fluid acceptance chamber accepting a high pressure working fluid into a housing block securing the electrode guide in the vicinity of the workpiece; and a high pressure working fluid jet opening disposed at a lower edge of the high pressure working fluid acceptance chamber and supplying a jet flow from the high pressure working fluid into an electrical discharge machining gap, characterized in that: the electrode guide is a hollow body and has a lower guide piece at the lower edge and an upper guide piece at the upper edge; the high pressure working fluid acceptance chamber is a hollow portion formed within the hollow body and a penetrated passageway for drawing the high pressure working fluid is formed within the hollow body and is communicated with the high pressure working fluid acceptance chamber, the high pressure working fluid acceptance chamber has a constant diameter from lower edge of the upper guide piece to the upper edge of the lower guide piece within the hollow body, the constant diameter of the high pressure working fluid acceptance chamber is several times larger than that of the electrode; the lower guide piece of the high pressure working fluid acceptance chamber has a funnel shape in which the diameter narrows from the diameter of the high pressure working fluid acceptance chamber into the diameter of the high pressure working fluid jet opening; the lower guide piece holding the high pressure working fluid jet opening which the electrode passes through is arranged such that the diameter of the high pressure working fluid jet opening is slightly larger than that of the electrode; and the jet flow of the high pressure working fluid is supplied into the electrical discharge machining gap so that it is not expanded so much. an electrode-for-machining being a stick-shaped electrode or a pipe-shaped electrode; an electrode guide for guiding a lower portion of the electrode in a Z axis direction through an interposed fluid layer of working fluid in the vicinity of a workpiece; a high pressure working fluid acceptance chamber accepting a high pressure working fluid into a housing block securing the electrode guide in the vicinity of the workpiece; and a high pressure working fluid jet opening disposed at a lower edge of the high pressure working fluid acceptance chamber and supplying a jet flow from the high pressure working fluid into an electrical discharge machining gap, characterized in that: the electrode guide is a hollow body and has a lower guide piece at the lower edge and an upper guide piece at the upper edge; the high pressure working fluid acceptance chamber is a hollow portion formed within the hollow body and a penetrated passageway for drawing the high pressure working fluid is formed within the hollow body and is communicated with the high pressure working fluid acceptance chamber, the high pressure working fluid acceptance chamber has a constant diameter from lower edge of the upper guide piece to the upper edge of the lower guide piece within the hollow body, the constant diameter of the high pressure working fluid acceptance chamber is several times larger than that of the electrode; the lower guide piece of the high pressure working fluid acceptance chamber has a funnel shape in which the diameter narrows from the diameter of the high pressure working fluid acceptance chamber into the diameter of the high pressure working fluid jet opening; the lower guide piece holding the high pressure working fluid jet opening which the electrode passes through is arranged such that the diameter of the high pressure working fluid jet opening is slightly larger than that of the electrode; and the jet flow of the high pressure working fluid is supplied into the electrical discharge machining gap so that it is not expanded so much. the electrode guide is a hollow body and has a lower guide piece at the lower edge and an upper guide piece at the upper edge; the high pressure working fluid acceptance chamber is a hollow portion formed within the hollow body and a penetrated passageway for drawing the high pressure working fluid is formed within the hollow body and is communicated with the high pressure working fluid acceptance chamber, the high pressure working fluid acceptance chamber has a constant diameter from lower edge of the upper guide piece to the upper edge of the lower guide piece within the hollow body, the constant diameter of the high pressure working fluid acceptance chamber is several times larger than that of the electrode; the lower guide piece of the high pressure working fluid acceptance chamber has a funnel shape in which the diameter narrows from the diameter of the high pressure working fluid acceptance chamber into the diameter of the high pressure working fluid jet opening; the lower guide piece holding the high pressure working fluid jet opening which the electrode passes through is arranged such that the diameter of the high pressure working fluid jet opening is slightly larger than that of the electrode; and the jet flow of the high pressure working fluid is supplied into the electrical discharge machining gap so that it is not expanded so much.