There is provided an application development system capable of easily developing an application which is capable of flexibly coping with the variation in system environment, such as a platform, and which has excellent maintainability. In the application development system, a design tool 1 supports the designing of an application, which is based on the combination of a plurality of logical components, on the basis of a logical component information 4, to output a logical design information 5 obtained by the designing of the application. A source generating part 2 and a compiler 3 produce an application (an executable file 9), which is executable on a specific platform, on the basis of the logical design information 5, which is outputted from the design tool 1, and a physical installation information (a physical component information 6 and a component library 8) for software components.