A performance evaluating apparatus includes a selector, a first performance value calculator, and a second performance value calculator. The first performance value calculator calculates a first performance value based on first partial process execution time tcpu in which a first processor performs a first partial process and a second partial process execution time tdisk in which a second processor performs a second partial process. The second performance value calculator calculates a second performance value based on the first partial process execution time and the predetermined upper limit executable time ratio α1. The selector selects either the first performance value or the second performance value as the performance value based on the upper limit executable time ratio, the first partial process execution time, and the second partial process execution time.