This thesis analyzes Japanese patent agents’ business in international patenting activities during the interwar period. The patent system in Japan has been open to foreign inventors since the country became a signatory of the Paris Convention in 1899. According to the Patent Law, all patents from abroad had be submitted to the Patent Office through the hands of the local agents. The key brokering role of these agents in international technology transfer around the patent system, however, has long been overlooked. This thesis investigates their technology intermediation using a mixed method: employing a fine-tuned Optical Character Recognition (OCR) model and natural language processing tools, I create a new dataset including the agents recorded in all patents granted in Japan from 1922 to 1940. Additionally, guided by the macro, quantitative analysis, this thesis also rediscovers various scattered primary sources to reconstruct the agents’ business scope and individual career. This thesis employs the theories on brokers and brokerage from sociology and anthropology, particularly examining the agents’ position in the international information network through the analytical lenses of brokers, gatekeepers and compradors. The main findings are that a specialized subdivision of this occupation focused specifically on the international patenting activities during these two decades, and a few of the most prestigious agents managed to balance their domestic and foreign clienteles. They actively aided foreign patentees in filling applications in Japan and finding local buyers for their inventions. Their business also extended to the neighboring countries, and particularly to Manchukuo, as the intellectual property protection institutions were slowly established in this region, simultaneously with the expansion of the Japanese Empire. As the only established specialist group in East Asia, these agents were an organic part of the emerging international professional community. Among these agents, the foreigners working in Japan and their successors sought to connect directly with international clients, while the large local patent agents relied more on transnational liaisons to reach foreign inventors.