In an intermediate connecting unit 50 of superconducting cables, by forming the connecting superconducting wires 101 in a trapezoid shape tapered in the direction of the electric insulating layer 113 (the superconducting shield layers 114) sides from the large radius section 213a side of the reinforcement insulating layer 213, the inclined surface sections 213b can be covered without spaces and without the plurality of connecting superconducting wires overlapping. The plurality of connecting superconducting wires 101 cover the inclined surface sections 213b of the reinforcement insulating layer 213 formed thicker than the radius of the cable cores 11 of the superconducting cables 10. The connecting superconducting wires 101 further connects the superconducting wires 10 arranged on the outer periphery of the large radius section 213a of the reinforcement insulating layer 213 and the superconducting wires 100 constituting the superconducting shield layers 114.