An optimization calculation method includes, generating individuals of a present generation with an individual selected in a previous generation as a parent individual using an algorithm for obtaining optimum solutions while evolving a plurality of individuals for each generation, evaluating each individual of the present generation, setting a constraint condition value of the present generation based on a constraint condition value of one generation before with respect to the present generation, and a constraint condition provisional value achieved by a half or more of individuals used for generating child individuals of a next generation, determining whether an evaluation result of each individual satisfies a constraint condition value of the present generation, changing for lowering an evaluation result of individuals which do not satisfy the constraint condition value of the present generation, and selecting individuals to be solution candidates from among individuals on which the determination or change process is performed.