This conservator is provided with the following: a housing (110) that contains a transformer oil (130); a rubber bag (120) that expands or contracts so as to contact the surface of the transformer oil (130) inside the housing (110); and an oil-level gauge that detects the position of the surface of the transformer oil (130) inside the housing (110). The oil-level gauge comprises a float (140), an arm (150) connected to one end of said float (140), and a display dial (160) that indicates the position of the surface of the transformer oil (130) in correspondence with the angle of the arm (150). The float (140) is connected to the arm (150) so as to be able to pivot relative thereto and extends away from the arm (150) along the bottom surface of the rubber bag (120). The length of the float (140) in the direction in which the float (140) extends is larger than the maximum thickness of the float (140).
