Abstract: The apparatus is intended for measuring the moisture content of moving dielectric materials. The apparatus comprises an aerial adapted to directly receive electromagnetic radiation signals caused by static electric discharges occurring at each moment of time between production apparatus and a moving dielectric material, the signals carrying information about the moisture content of the material. The aerial is connected to a bandpass tuned filter, a detector, an inverter and a recording device, all of which are connected in series. The apparatus may be provided with one or two comparators to prevent the occurrence of a false signal when the moving material breaks up and to register overloading of the device.