A measuring device that is able to function even in rough environments, for example under great heat or in environments in which water or steam is found, as is the case in rolling mills, among other environments, has a housing, a central measuring device that passes through the housing in a straight line, and a measuring coil that is disposed in the housing and encloses the measuring opening. The device has a coil carrier that is disposed in the housing radially outside of the measuring coil and carries the measuring coil.