Terminal structure of superconducting cable system

A superconducting cable terminal connection device connecting a terminal of a superconducting cable for power transmission to an external power system, includes: an electric field relaxation shield disposed inside an insulation housing; a horizontal conductor fixed to an end portion of a core of the superconducting cable drawn into the electric field relaxation shield; an insulator which coats an outer periphery of the horizontal conductor; a vertical conductor which is drawn into the electric field relaxation shield and has a through-hole through which the horizontal conductor and the insulator pass so as to be slidable in a lengthwise direction; and a flexible electrical conduction member which electrically connects an end portion of the horizontal conductor to the vertical conductor.