1. An application execution time reducing method comprising: a native function registering step of, when processing of an application in a software structure having a native function which is a basic component is started, registering information about the native function onto a platform on which the native function can be executed; a native function step of executing the native function on the platform by using the information about the native function; and a native function deleting step of, when the processing of the application is quitted, deleting the information about the native function from the platform.