Provided are an apparatus for generating/detecting terahertz wave and a method of manufacturing the same. The apparatus includes a substrate, a photo conductive layer, a first electrode and a second electrode, and a lens. The photo conductive layer is formed on an entire surface of the substrate. The first electrode and a second electrode are formed on the photo conductive layer. The first and second electrodes are spaced from each other by a certain gap. The lens is formed on the first and second electrodes. The lens is filled in the gap between the first and second electrodes.