1. A method of production planning, for calculating out production amount and/or supply amount and/or transportation means at a plural number of points of production, material supply and/or marketing, comprising steps of: putting a relationship between a target value of a predetermined management index and an estrangement value therefrom into restriction condition, when formulating the restriction condition into a linear programming problem; and calculating out a feasible production plan, so that the estrangement between said predetermined management index and the target value thereof, being calculated from an executable solution of said linear programming problem, comes to be minimal.