The aim of this paper is to examine the concept and its state of the art towards sustainable tourism development, which is a tourism under the condition of natural & cultural preservation and can be classified roughly into selective tourism and sustainable mass tourism. This paper clarifies what kind of policies will be required to promote sustainable tourism through the analyses of quantitative data of tourism and development in thirty-six developing countries. Moreover, six indices representing each aspect of demand, supply, income, income & expenditure, development level and preservation level are adopted and the real state of tourism development is examined by the correlation analyses between these six indices and macro indices related with country scale. Particularly, the tourism has an important role to acquire foreign currency in small countries and actual state of tourism development in these countries is examined carefully.