In order to understand the emerging process of office agglomeration propelled by transnational corporations in Singapore, it is important to pay attention to the transactions between buyers and suppliers. This paper aims to clarify how and why Japanese electronics firms have allocated International Procurement Offices (IPOs) to Singapore, and to demonstrate the buyer-supplier relations through IPOs. Japanese firms, responding to the appreciation of the yen against the dollar and the deregulation of trade and investment, have distributed plants more intensively among Southeast Asian countries since the mid-1980s. These firms have also relocated the purchasing functions from Japan to these countries for the purpose of providing parts and components for those plants. The main intention behind the relocation was to reduce the risk of foreign-exchange loss in the region where the key currency was the dollar. It should also be noted that the lower price of parts and components in the region was another inducement. However, from the mid-1980s to the mid-1990s, Japanese firms rarely installed their purchasing functions in the plants in the region, instead deciding to establish IPOs independently in Singapore. This was because most Southeast Asian countries, unlike Singapore, had insufficient industrial infrastructure at that time. In addition, the agglomeration of suppliers in Singapore, not only consisted of those factories but also of sales offices, and this was an important factor for firms deciding on the location of their IPOs. Nevertheless, these firms' plants have become able to purchase customized parts and components such as chassis and mechanical components since the mid-1990s because of the improving basic structure of industries in Malaysia, Thailand, and so on. Along with this progress, Japanese firms began to move this kind of purchasing function out of Singapore and incorporate it into plants in other Southeast Asian countries. However, the function of purchasing standardized parts like electronic parts a