A fixing structure of a radial lead of a rotating electrical machine, comprising: slip rings (2a, 2b) provided to a rotation shaft of a rotor; and axial leads provided inside a center hole of the rotation shaft and configured to supply a current to a rotor coil; wherein the fixing structure is configured to prevent a leakage of a refrigerant gas within the rotation shaft, wherein - the radial lead is inserted into a radial lead hole penetrating through the rotation shaft in a radial direction from the center hole, and - a male screw formed at one end is threaded into a female screw formed in the axial lead and fixed therein while the other end is electrically connected to the slip ring (2a, 2b); and - a sealing member installed to a step portion of the radial lead hole is fastened, via a spacer (19, 21, or 22), by a fastening nut threaded onto the other end of the radial lead, so that a side of the center hole is maintained airtight from the outside, and characterized in that - a tapered surface continuing to an inner peripheral surface of the radial lead hole in which the sealing member is installed and spreading toward an external opening end is formed; - the fixing structure has a ring-shaped tapered member that fits to the tapered surface; and - the tapered member is interposed between the sealing member and the spacer (21 or 22). slip rings (2a, 2b) provided to a rotation shaft of a rotor; and axial leads provided inside a center hole of the rotation shaft and configured to supply a current to a rotor coil; wherein the fixing structure is configured to prevent a leakage of a refrigerant gas within the rotation shaft, wherein - the radial lead is inserted into a radial lead hole penetrating through the rotation shaft in a radial direction from the center hole, and - a male screw formed at one end is threaded into a female screw formed in the axial lead and fixed therein while the other end is electrically connected to the slip ring (2a, 2b); and - a sealing member installed to a step portion of the radial lead hole is fastened, via a spacer (19, 21, or 22), by a fastening nut threaded onto the other end of the radial lead, so that a side of the center hole is maintained airtight from the outside, and characterized in that - a tapered surface continuing to an inner peripheral surface of the radial lead hole in which the sealing member is installed and spreading toward an external opening end is formed; - the fixing structure has a ring-shaped tapered member that fits to the tapered surface; and - the tapered member is interposed between the sealing member and the spacer (21 or 22). - the radial lead is inserted into a radial lead hole penetrating through the rotation shaft in a radial direction from the center hole, and - a male screw formed at one end is threaded into a female screw formed in the axial lead and fixed therein while the other end is electrically connected to the slip ring (2a, 2b); and - a sealing member installed to a step portion of the radial lead hole is fastened, via a spacer (19, 21, or 22), by a fastening nut threaded onto the other end of the radial lead, so that a side of the center hole is maintained airtight from the outside, and - a tapered surface continuing to an inner peripheral surface of the radial lead hole in which the sealing member is installed and spreading toward an external opening end is formed; - the fixing structure has a ring-shaped tapered member that fits to the tapered surface; and - the tapered member is interposed between the sealing member and the spacer (21 or 22).