The invention relates to an apparatus for monitoring a field device for determining and/or monitoring a physical and/or chemical process parameter of a process medium with a first sealing stage facing toward the process and at least one housing with a predetermined interior volume. The housing is located on the side of the first sealing stage facing away from the process, wherein energy is transferable through the first sealing stage 4 in the direction of the process medium. This energy interacts with the process medium, wherein at least one detector unit is provided in the housing, which unit monitors at least one condition parameter of the interior volume of the housing. A control/evaluation device determines, on the basis of the energy interacting with the process medium, the physical and/or chemical process parameter, and wherein the control/evaluation unit and/or another monitoring unit recognizes and/or seals off and/or issues an alarm, on the basis of the monitored condition parameter in the interior volume of the housing, as soon as the monitored condition parameter in the interior volume of the housing a predetermined limit value.