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.).