A processor stores authentication information managed by a native environment of the communication terminal in a first storage region of the storage device. The processor stores authentication information of an application to be executed on a Web application execution environment of the communication terminal in a second storage region of the storage device. The processor performs a control to write the authentication information stored in the first storage region to the second storage region when authentication information used by the application is not stored in the second storage region and is stored in the first storage region.