A current transformer fixing device comprises a current transformer cylinder surrounding the periphery of a central conductor to be connected to an electric power line, a cylindrical container surrounding the outer peripheral side of a current transformer arranged on the outer peripheral side of the current transformer mounting cylinder and containing the current transformer, a transformer mounting plate connecting the bottom side of the current transformer mounting cylinder and the bottom side of the cylindrical container to each other and restricting axial movement of the current transformer, a sealing flange connected to the upper end of the cylindrical container with a gap between the sealing flange and the upper end of the current transformer mounting cylinder, and fixing bolts fastened to the sealing flange in an axial direction of the conductor and restricting axial movement of the current transformer.