PURPOSE: To update the plan in a short time by receiving a signal of a change setting part for designating an item which necessitates a change, executing replanning related to a designated item, and sending a new plan to a storage part.

CONSTITUTION: By a planning part 4, a plan is generated at ever item of the plan, and also, a tag is attached to each item, and in its tag, a condition at the time of generating the item and a related condition to other item of the item are entered, and this plan is stored in a plan storage part 5. On the other hand, an information processing part 1 inputs external information, processes the information and sends it to a state evaluating part 2, and the state evaluating part 2 receives signals from the information processing part 1 and the plan storage part 5, evaluates a state and sends it to a change setting part 3. Subsequently, the change setting part 3 designates an item which necessitates a change in each item of a plan, based on the information of each tag from this signal, and the planning part 4 executes replanning related to the designated item from its signal and sends a new plan, that is, an updated plan to the plan storage part 5. In such a way, by replanning only the item of the necessary minimum in accordance with a variation of the state, the plan is updated in a short time.