Abstract: A detector for detecting leakage or weak points in a package which is continuously moveable relative to the detector includes a detector element which is resiliently mounted for movement transverse to the feed direction of the package. The detector element includes at least one electrical conductor and a guiding part for guiding the electrical conductor toward that part of the package which is to be detected.

Abstract: A pinhole detecting apparatus includes a first electrode which may be a needle electrode or a brush electrode. The first electrode is positioned to be closed to or brought into contact with a member to be detected such as an insulation sheet which seals food, a closed container which contains medicine, or the like. Such a member to be detected is put on a second electrode which may be a conveyer made of electrically conductive material. When a high voltage is applied between the first and second electrodes, if a pinhole was formed on the member to be detected, a discharge current flows between the first and second electrodes through the pinhole, whereby the pinhole can be detected through detection of such a discharge current. A portion of the member to be detected below the first electrode is cooled by an air stream or other coolant when the high voltage is applied to the first and second electrodes, whereby the portion of the member to be detected is prevented from being thermally destroyed.