An information terminal device, which provides information for navigation to a set destination, the information terminal device comprising: a CPU for performing computing processing; a memory for storing information; a location information detecting module for detecting a current location; a navigation module for calculating location information from the detected current location and from map information, and for calculating navigation information with respect to a set destination; a display unit for displaying the location information and the navigation information; a communication module for communicating over a network; and a widget management module for managing execution of a widget, which is a single-function program that is displayed all the time in a part of the display unit and managing a device state flag, wherein the widget management module comprises: a policy determining module for setting to the widget an operation policy, which comprises an operation restriction concerning a display state on the display unit and a priority; characterised in that the widget management module further comprises a reliability determining module for determining reliability of the widget, and wherein, when the device state flag reaches a driving state in which the detected current location changes or a navigation state in which the detected current location changes and the navigation information is output to the display unit as well, the widget management module is configured to restrict operation of the widget in accordance with the operation restriction and the reliability, and to display on the display unit preferentially the location information and the navigation information. a CPU for performing computing processing; a memory for storing information; a location information detecting module for detecting a current location; a navigation module for calculating location information from the detected current location and from map information, and for calculating navigation information with respect to a set destination; a display unit for displaying the location information and the navigation information; a communication module for communicating over a network; and a widget management module for managing execution of a widget, which is a single-function program that is displayed all the time in a part of the display unit and managing a device state flag, wherein the widget management module comprises: a policy determining module for setting to the widget an operation policy, which comprises an operation restriction concerning a display state on the display unit and a priority; characterised in that the widget management module further comprises a reliability determining module for determining reliability of the widget, and wherein, when the device state flag reaches a driving state in which the detected current location changes or a navigation state in which the detected current location changes and the navigation information is output to the display unit as well, the widget management module is configured to restrict operation of the widget in accordance with the operation restriction and the reliability, and to display on the display unit preferentially the location information and the navigation information. a policy determining module for setting to the widget an operation policy, which comprises an operation restriction concerning a display state on the display unit and a priority; characterised in that the widget management module further comprises a reliability determining module for determining reliability of the widget, and wherein, when the device state flag reaches a driving state in which the detected current location changes or a navigation state in which the detected current location changes and the navigation information is output to the display unit as well, the widget management module is configured to restrict operation of the widget in accordance with the operation restriction and the reliability, and to display on the display unit preferentially the location information and the navigation information.