Due to the rise of maritime trade following the 9th century, the Song state was confronted with the task of newly administrating coastal regions. Maritime Trade Offices 市舶司 were charged with trade and diplomatic relations within the coastal regions during the Song. The chief aim of this study is to elucidate the role of the Maritime Trade Offices in the administration of trade by using the documents exchanged by those offices. In contrast to most earlier studies of the Maritime Trade Offices that chiefly focused on their place in the government, I believe it is possible to make clear a new aspect of the administration of the Maritime Trade Offices and by extension the coastal administration of the autocratic central government by dealing with the issuing and exchange of documents by the offices. The Maritime Trade Offices issued permits 公憑 to Chinese maritime merchants. And as regards documentation, the merchants would submit documents listing cargo and destination of their ships to the provinces; and after examining the documents, the provinces would forward them to the Maritime Trade Offices, which would then issue permits. The procedures for issuing the documentation was set by imperial edict in the Yuanyou 元祐 era, but permits had been issued previously; the urgent need for the administration of a Maritime Trade Offices in regional areas had been recognized, and thus the administration of the Maritime Trade Offices began from a single region. In addition, when confronted with problems in maritime regions, the Maritime Trade Offices strove to obtain information through the exchange of documents such as guan 關, which were exchanged between various Maritime Trade Offices and local officials of equal rank in the same region. In the end, it was difficult to grasp the actual amount of profit gleaned from the irregular trade because it wasn't were no regular levy 常賦. Despite this fact, following the Shaoxing 紹興 era when national finances became dependent on the income from maritime trade, the Ministry of Revenue could not grasp the actual figure even though financial reporting to the ministry had become important, and thus it permitted financial administration to be conducted at the local level. As a result, the dependency on maritime trade as a source of revenue for national finances was linked to the elimination of the Maritime Trade Offices in the Liangzhe 兩浙 region. As can be seen from the above, the administration of the Liangzhe region by the Maritime Trade Offices during the Song dynasty had been conducted on a regional basis through the Northern Song, but from the Southern Song onward the national government strengthened its control of government finances and the local offices in the Liangzhe region were ultimately abolished, which can be seen as part of the general process of concentrating control of maritime trade affairs in the central government.