AbstractIt is very important from the viewpoint of environmental electromagnetic engineering to detect vectors of high‐frequency currents on a metal plate (high‐frequency surface currents). In this paper, a high‐frequency surface current detector has been realized based on the coupling theory between an electromagnetic plane wave and a wire above the earth, and by modelling this arrangement. For the modelling, it has been considered that the electric field is approximately perpendicular to the metal plane in the space near its surface due to the surface currents flowing along the plate; and that the magnetic field is parallel to the metal plane. In practice, the pointing vector carried by the magnetic field is measured. It has been confirmed that the detector actually made can detect the vectors of surface currents by detecting progressing waves generated along a metal plane. the coupling coefficient between the surface currents and detector has been obtained experimentally by varying the parameters of the coupling line.