A device for inspecting rings and necks of containers includes a movable element with an outer gauge for checking the outside of the ring of the containers, and an inner gauge for checking the inside of the ring and neck of the containers. The movable element includes a system for measuring the position of the movable element relative to the frame, a system for detecting contact between the inner gauge and the container, a system for detecting contact between the outer gauge and the container, and a processing unit for determining, on the basis of the measurements of the position of the movable element and of the instances of contact between the gauges and the container, whether or not the size of the rings and/or necks of the containers are acceptable, and the types of defects for the containers whereof the sizes of the rings and/or necks are not acceptable.