There is provided a mobile communication device comprising an environment as a mobile communication device platform and an application execution environment configured on the mobile communication device platform. The application execution environment has a function of a first software interface, for receiving an operation regarding a wallpaper setting which is used by a wallpaper setting program as a default application operating on the mobile communication device platform, for a user setting application operating on the application execution environment. The mobile communication device platform has a function of a second software interface, for receiving an operation regarding the wallpaper setting which is used by the wallpaper setting program, for the application execution environment. An instruction for an operation regarding the wallpaper setting issued from the user setting application is reflected in the wallpaper setting via the first software interface and the second software interface.