The present invention is provided with a threat analysis processing unit that, on the basis of an analysis result from the vulnerability analysis unit, analyzes a threat to the system and outputs a threat analysis result; a countermeasure planning unit that, on the basis of the threat analysis result and vulnerability information, plans the countermeasure plan which reduces the impact of the vulnerability; a security test planning unit that plans the security test on the basis of the countermeasure plan; an evaluation calculation unit that performs an evaluation on the basis of the security test, and outputs an evaluation result; and a result processing unit that processes the evaluation result and generates a security countermeasure.