In a method for producing a sensor element, a silicon nanowire having a diameter less than 50 nm is contacted via at least two points by electrodes. The nanowire and the electrodes are arranged on one plane on a substrate. Catalytically active metal nanoparticles having a diameter in the range of 0.5-50 nm are deposited on the surface of an insulating substrate and the surface and the metal nanoparticles deposited thereon are exposed to a gas flow containing a gaseous silicon component at a temperature in the range of 300-1100° C., whereupon, during a time period in the range of 10-200 minutes, a nanowire of a length in the range of 5-200 μm projecting from the substrate is formed. The nanowire projecting from the surface of the substrate is deposited in one plane with one of the contact surfaces corresponding to the surface of the insulating substrate by applying a secondary substrate, and either the nanowire deposited on the insulating substrate is contacted at two different points by electrodes or the nanowire adhering to the secondary substrate is contacted at two different points by electrodes.