A chemical sensor using metal nano-particles and a method for manufacturing a chemical sensor using metal nano-particles are provided. The chemical sensor includes: metal nano-particles; single-ligand organic molecules (or a single molecule) that binds to the metal nano-particles by using a metal bonding functional group; a substrate bonding functional group formed at the metal nano-particles and the single-ligand organic molecules as bound to each other; a substrate; electrodes formed on the substrate and having an interdigitate (IDT) structure; and a substrate functional group formed on the substrate and positioned between the electrodes, wherein the substrate bonding functional group and the substrate functional group are covalently bonded.