To provide a device determining an optimum cutting method in a short time even in the case of large n value, relating to a two-dimensional plane cutting method optimizing device obtaining an optimum cutting method minimizing a waste area, in the case of cutting out a prescribed number of sheets of small planes from a number of n sheets of two-dimensional planes.

A two-dimensional plane cutting information acquisition part 2 acquires information of how to cut pattern or the like relating to cutting of a two-dimensional plane. In a fitness function setting part 3, a weight coefficient is set to a fitness function used in an optimization processing part 4. In the optimization processing part 4, based on information obtained from the plane cutting information acquisition part 2, a group of chromosome, represented by a row or the like of how to cut pattern number in accordance with each two-dimensional plane, is generated, by genetic algorithm, genetic operation of selection, crossing, sudden variation of the chromosome is repeated, optimum solution or that approximate to the optimum solution is obtained.