An inspection device for the rings and necks of containers, the device comprising: • movable equipment driven relative to a stand with reciprocating motion in a travel direction parallel to the axis of symmetry of containers and over a maximum stroke, the movable equipment being provided at least with a first inspection gauge (14, 15) for inspecting the rings and/or necks of containers, which gauge is movably mounted relative to the movable equipment in a travel direction parallel to the travel direction of the movable equipment; • a measurement system for measuring the position of the inspection gauge relative to the stand in the travel direction when contact occurs between the inspection gauge and the container, the measurement system being connected to a processor unit; and • a processor unit responding to the measured positions of the movable equipment in the event of contact occurring between the gauge (14, 15) and the container in order to determine whether the dimensions of the rings and/or necks of containers are acceptable and to determine the types of defects of containers that have dimensions that are not acceptable; • the measurement system comprising a contactless transceiver system for emitting and receiving a light beam along a path in which there is arranged a target that is securely mounted to the first inspection gauge, the transceiver system being secured to the stand, and delivering measurements continuously of the position of the first inspection gauge relative to the stand; and • the processor unit comprising means for detecting when the measurements of the position of the first inspection gauge (14, 15) delivered by the transceiver system cease varying, in order to determine that contact has occurred between the first inspection gauge and the container. • movable equipment driven relative to a stand with reciprocating motion in a travel direction parallel to the axis of symmetry of containers and over a maximum stroke, the movable equipment being provided at least with a first inspection gauge (14, 15) for inspecting the rings and/or necks of containers, which gauge is movably mounted relative to the movable equipment in a travel direction parallel to the travel direction of the movable equipment; • a measurement system for measuring the position of the inspection gauge relative to the stand in the travel direction when contact occurs between the inspection gauge and the container, the measurement system being connected to a processor unit; and • a processor unit responding to the measured positions of the movable equipment in the event of contact occurring between the gauge (14, 15) and the container in order to determine whether the dimensions of the rings and/or necks of containers are acceptable and to determine the types of defects of containers that have dimensions that are not acceptable; • the measurement system comprising a contactless transceiver system for emitting and receiving a light beam along a path in which there is arranged a target that is securely mounted to the first inspection gauge, the transceiver system being secured to the stand, and delivering measurements continuously of the position of the first inspection gauge relative to the stand; and • the measurement system comprising a contactless transceiver system for emitting and receiving a light beam along a path in which there is arranged a target that is securely mounted to the first inspection gauge, the transceiver system being secured to the stand, and delivering measurements continuously of the position of the first inspection gauge relative to the stand; and • the processor unit comprising means for detecting when the measurements of the position of the first inspection gauge (14, 15) delivered by the transceiver system cease varying, in order to determine that contact has occurred between the first inspection gauge and the container.