PURPOSE: To form an optimum production plan by grasping the load and capacity of a production field, and when the capacity is over, moving the load in a time backet direction and a process direction.

CONSTITUTION: A production plan (reference production scheduling 12) in converted into a load of a process unit/time bucket unit, lot progress and process operating status in the production field are converted into a load of the process unit/time bucket unit and the capacity of the process unit/time bucket unit is calculated from a production field model 22. The converted loads are stacked and a process/time bucket maximizing a difference between the stacked result of the loads and the capacity is decided. In the process/time bucket maximizing the difference between the load and the capacity, the movement of each load in the process direction and the time bucket direction is evaluated and the load maximizing an evaluation value indicating a smoothing rate calculated from the difference between the load and the capacity is moved in the maximum direction. Thereby the fine adjustment of the production plan can be attained while optionally moving the load in each time backet.