The management server includes a policy storage that stores a security policy, and a first hardware processor that, in response to reception of a preparation completion notification from each of all of two or more information processing apparatuses, outputs an update instruction to each of the two or more information processing apparatuses. Each of the plurality of information processing apparatuses includes a security information storage that stores security information, and a second hardware processor that executes a process using any of the stored security information, acquires new security information corresponding to security information to which the reference date and time, which the current date and time have passed, correspond, transmits a preparation completion notification to the management server, and in response to reception of the update instruction from the management server, updates the security information with the new security information.