A power transmission cable with easy laying, reduced heat invasion and enhanced efficiency. The cable comprises an inner pipe 105 encasing a refrigerant passage 101, a superconducting member 102 and an electrically insulating portion 103; an outer pipe 106; a vacuum adiabatic insulating section 104 between the inner and outer pipes; an inner pipe support ring disposed between the inner and outer pipes so that it is slidable along the outer side of the inner pipe; an outer pipe support ring fixed to the inner side of the outer pipe; and a support member which is disposed between the inner and outer pipe support rings.