[en] A device has been designed to increase the accuracy and to widen the scale of simultaneous measurements of density and humidity of soil surface layers. The device involves a gamma-densitometer, a neutron humidity measuring apparatus, and knife-like legs with gamma- and neutron sources from one end relevant detectors from the other. The legs are attached to a special cart by a fixator providing for their vertical displacement. Higher accuracy and wider scale of measurements are provided by the detectors being placed into clamshell holders and situated in a cantilever position with respect to the legs. A scheme of the device is given