Single electron transistors exhibiting transport properties based on a single Coulomb island have been fabricated using ultra-thin gold nanowires (AuNWs), which are synthesized via a chemical reduction process. The AuNWs are bottom-contacted with source and drain electrodes to avoid damaging the AuNWs under fabrication processes. We investigate the transport properties in the fabricated devices as a function of the bias and gate voltages at room and low temperatures. At 0.23 K, the periodical Coulomb oscillations and diamonds are clearly observed indicating that an individual AuNW acts as a single Coulomb island. These transport properties can be explained by the orthodox Coulomb blockade theory.