The computer aided planning support system of this invention is constructed of a planning information input device from which an object data for making a plan is inputted; an object data storage unit for storing the inputted object data; a planning unit for making a plan by reading the object data stored in the object data storage unit and processing the read-out data in accordance with a planning program; a planning data storage unit for storing the data associated with the plan made by the planning unit; a planning data processing unit for processing the planning data stored in the planning data storage unit in accordance with a predetermined scheduling function and sending the processed data to the planning unit; and a planning information output device for outputting the planning result generated by the planning unit in the form a user can use it.