This book presents a new comprehensive study on the impacts of population decline on infrastructure in Japan, taking into account all types of infrastructure and using a quantitative approach. Data collection methods include interviews and two large scale questionnaire surveys, the first conducted with municipalities and the second, a stated preference survey, conducted with members of the public. The goal of sustainable development is relevant even in a depopulated society, and hence a sustainable development framework is applied to the analysis where social, economic, environmental and engineering impacts are investigated. The main findings indicate that some infrastructure impacts observed and reported in depopulated areas do not seem to be related to any population decline; moreover, the preferences of citizens for infrastructure development is very similar between depopulated areas and non-depopulated areas. This book also provides many cases to cope with the impacts of population decline on infrastructure in Japan. Some of policy implications in each four-aspect of sustainable infrastructure development and management could be extracted from those cases.