PURPOSE: To plan a production program fitted to the optimum production lot size and production capacity per day by allocating the number of objects necessary for the processing for production to each processing start day with its leveling based on the production capacity number per day and optimum processing number.

CONSTITUTION: A scheduling part 4 calculates a production necessary number N2=N - N1 by respectively reading a production program number N for a production objective term P1 from a production planning part 1 and a product in stock number N1 from a stock data part 3, and calculates an input necessary number N3=N2/Y by reading a yield Y from a reference information part 2. Moreover it calculates while from an input started day T1,s to input completion day T1,e retroactive to a manufacture term L only so that the initial production and final production are respectively completed in a production completed initial day P1,s and production completion final day P1,e, by reading a calender and manufacturing term L from the reference information part 2. The input number (n) per day is then calculated and output to a scheduling output part 5 as the input scheduling of input object terms T1,e - T1,s.