To reduce manhour for the preparation of a scenario by simply describing the scenario of navigation by a mode retrieving instruction.

A scenario input means 1 inputs a scenario describing the story of automatic navigation and converts the scenario into an action table in which action to be executed by a GUI object or a node retrieving means 5 is allowed to correspond to an event for starting the action. An action managing means 3 manages the action table. A scenario execution means 4 receives start action from the input means 1, executes the received action, finds action corresponding to an event issued by the execution of the start action from the action table stored in the means 3, executes the action, and then executes succeeding action from an event issued from the preceding action so as to successively execute the chain of events and action.