This article aims to inquire regional inequalities and economic development policies of Southeast Asian countries and to analyze problems of government’s policies. This article selected Indonesia among maritime nations and Vietnam among continental nations in Southeast Asia. As a result, this article found that regional inequality of two countries did not decrease in spite of their economic development, and economic development policies of two countries exacerbated regional inequality. And, Failures of adjust authority between central government and local government obstructed reasonable adjustment of resource distribution and effective execution of development plan. This article suggests the necessity of reconsidering economic development policies and readjusting authority between central government and local government for easing regional inequality in Indonesia and Vietnam.