The invention discloses a micro-sensor for sensing a chemical substance. The micro-sensor according to the invention includes a substrate, a micro-cantilever, an electrode structure, and a measuring device. The micro-cantilever is formed on the substrate and has a capturing surface for capturing chemical substances. The electrode structure is for supplying an electrical field. The electrical field is disposed so as to assist the capturing surface in capturing chemical substances. The measuring device, coupled to the micro-cantilever, is for measuring a variation on a mechanical property of the micro-cantilever induced by the captured chemical substance and interpreting the variation on the mechanical property of the micro-cantilever into information relative to the chemical substance.