Abstract: An object of the present invention is to provide a portable electronic device of which operability is improved while maintaining a security function, and to provide a control method and a control program for the portable electronic device. In a case in which a function setting operation key is operated, a function limiting unit displays a screen for requesting password (for example, a personal identification number, a password, etc.) on a display unit, and limits utilization of a function assigned to the function setting operation key (for example, a variety of setting, an address book function, an electronic mail function, etc.).

Abstract: An object of the present invention is to provide a portable electronic device of which operability is improved while maintaining a security function, and to provide a control method and a control program for the portable electronic device. In a case in which a function setting operation key is operated, a function limiting unit displays a screen for requesting password (for example, a personal identification number, a password, etc.) on a display unit, and limits utilization of a function assigned to the function setting operation key (for example, a variety of setting, an address book function, an electronic mail function, etc.).

Abstract: Provided is a mobile electronic device which enables a user to easily and intuitionally perform an application start operation in accordance with a user's preference. The mobile electronic device includes: an application execution unit (201); an operation unit (202) having an operation key group (11) and a rotary dial unit (41); and an operation control unit (203) for controlling various processes accompanying an operation through the operation unit (202). When a predetermined application is being executed by the application execution unit (201), the operation control unit (203) allocates a processing function relating to the predetermined application to a plurality of setting positions of the rotary dial unit (41). Upon detection of an input through the operation key group (11) while a predetermined application is being executed, the application execution unit (201) executes the processing function allocated to a predetermined setting position of the rotary dial unit (41).