A photoconductive antenna is adapted to generate terahertz waves when irradiated by pulsed light. The photoconductive antenna includes a first conductive region, a second conductive region, and a semiconductor region. The second conductive region is spaced apart from the first conductive region to form a gap therebetween in a top plan view of the photoconductive antenna. The semiconductor region is positioned in the gap between the first conductive region and the second conductive region in the top plan view. An interfacial surface of the semiconductor region positioned in the gap is flush with first interfacial surfaces of the first and second conductive regions. Second interfacial surfaces of the first and second conductive regions positioned on an opposite side from the first interfacial surfaces are positioned on the same side with respect to the interfacial surface of the semiconductor region positioned in the gap.