The gas insulated transmission line includes: a pair of conductors disposed in a length direction; a fixed-side socket and a movable-side socket respectively coupled to one ends of the conductors; and a conductive flexible member interposed between facing end surfaces of the fixed-side socket and the movable-side socket, both ends of the conductive flexible member being closely adhered to the end surfaces of the fixed-side socket and the movable-side socket to keep electric contact therebetween, and the conductive flexible member being expanded or shrunken in an axial direction according to thermal expansion/shrinkage of the pair of conductors. The gas insulated transmission line provides a wide axial contact area while allowing thermal expansion/shrinkage of conductors.