Now, about 30-50 million people are infected by malaria and 1-3 million people are infected by dengue. It is thought that the habitation range of these viruses will be spread bythe climate change. In this research, we studied the relations among climate conditions and malaria, dengue fever. Consequently, climate change might make the infection area expand especially in the tropics in Africa and South America, and unless temperature doesn't go up extremely, malaria will decrease in the Middle East. Moreover, when the living standard increases to some extent, the influence will reduce substantially. As for the case of dengue fever, unlike the case of malaria, the influence by temperature is little influenced by the economic. The influence by temperature was large and the rate of increase in South America is also very large especially in the South Pacific area.