An application development assistance system in which optimal security measures can be taken at positions in need of security measures under an application development environment using a flow diagram analyzes an input application description file and outputs application data information and module information. A data importance level judgment unit decides importance levels of data exchanged between modules on the basis of the application data information. A module exploitability judgment unit decides an exploitability score of each module on the basis of the module information and exploitability information read out from a module exploitability database; and a security function disposal position judgment unit decides disposal positions of security functions on the basis of data importance level information decided by the data importance level judgment unit, the exploitability score of each module decided by the module exploitability judgment unit, and security measure information read out from a security measure information database.