A noncontact voltage sensor is housed in a container comprising a container body having an opening on one side and an insulation cover body for sealing the opening. A plate type electrode insulated from a ground is housed in the container. The cover body side is opposed to a charging part of such as cables of an aerial line. A voltage is induced in the plate type electrode due to aerial electric charges between the charging part and the plate type electrode in the container, allowing detection of the voltage in the charging part. The cover body of the noncontact sensor is made of a fluorine containing resin such as an ethylene tetrafluoride resin to prevent a water film from forming on the outside surface of the insulation cover body and causing deterioration of the detection.