Abstract: Disclosed are a method of manufacturing a diamond electrode by a chemical vapor deposition (CVD) process, and a diamond electrode manufactured by the method. The method of manufacturing the diamond electrode includes: introducing a carbon source gas to form niobium carbide (NbC) on a niobium substrate, immediately before depositing an electrically conductive diamond layer on the substrate by a hot-filament chemical vapor deposition (HFCVD) process; and depositing electrically conductive diamond layers on the substrate by two or more separate processes. Accordingly, a pinhole present during deposition of the electrically conductive diamond layer is filled such that the contact between an electrolyte and the substrate in an electrolytic environment will be minimized so as to retard the corrosion of the substrate, thereby providing a diamond electrode having a long life span.