A measuring device includes: a measuring transducer accommodated, at least partially, in a housing, for registering at least one, measured variable; and a measuring device electronics electrically connected, at least at times, with the measuring transducer. The measuring device electronics includes at least one measurement channel for registering and further processing at least one primary signal generated by means of the measuring transducer, and an electrical current measuring circuit for registering measuring-device-internally flowing, electrical currents. Furthermore, it is provided, that the electrical current measuring circuit registers, during operation, at least at times, especially recurringly, an electrical leakage current, which flows as a result of a potential difference existing, at least at times, between housing and measuring device electronics and as a result of an electrically conductive connection likewise existing between housing and measuring device electronics, especially an undesired, electrically conductive connection and/or an electrically conductive connection formed by a deposit affecting the housing. Taking into consideration the registered leakage current, the measuring device electronics generates, additionally, at least one state value, especially a digital state value, instantaneously representing an operating state, especially a defective operating state, of the measuring device.