An accounting system under standard costing as absorption costing which identifies a break-even point, performs a process in which, in a break-even chart represented as a standard-costing marginal profit chart for a company or business line departments, a “net carryover manufacturing overhead allocation cost” η of an inventory and a managed gross profit QM (=Sales Amount X−Sales Absorption Cost) are defined, a managed fixed cost F (=η+Manufacturing Overhead C+General Administrative Cost G) is treated as a fixed cost, and the point of intersection between line segment OB′ connecting the origin O (0, 0) and point B′ (X, Vs) and horizontal line segment EN′ taking the value of the managed fixed cost F is identified as a break-even point (point H2′). Here, Vs is the sum of the managed gross profit QM and a sales manufacturing overhead allocation cost ACX.