Load test is executed with an appropriate frequency which does not lead to a decrease in software development efficiency and a decrease in the precision of software aging detection. Load test of a version of software under test is executed in accordance with an execution criterion, presence or absence of a software aging problem is detected by comparing a test result of the load test with a test result of load test of a previous version of the software to be compared, and frequency of execution of subsequent load test is adjusted by changing the execution criterion based on a result of the detection.
