Abstract: A remote temperature and/or temperature difference measuring device which includes a measuring circuit having a heat flux sensor for sensing the heat flow from an area on the surface of a body, and a portable housing which supports the sensor and also a device for determining or marking the area of analysis. The measuring circuit includes the heat flux sensor, a memory circuit connected to the heat flux sensor, and a storage input device such as a push button for initiating, at any given moment, the memory circuit's storage of a reference signal from the heat flux sensor. The measuring circuit also includes a comparator of which one of the inputs receives the output signals from the heat flux sensor, while the other input is connected to the memory circuit providing the reference signal. The comparator thus outputs a signal which corresponds to the difference between the reference signal and a subsequently received heat flux sensor output signal.