A partition reconfiguration system includes a management node that issues a partition reconfiguration instruction based on pre-defined schedule information; an operating system that, in response to the instruction, changes an operation state thereof to a partition re-configurable state in which a usual operation state is stopped to make reconfiguration possible and, at the same time, notifies that the operation state thereof has been changed, the operating system operating on a computer system; and a service processor that, in response to the notification notifying that the operation state has been changed, configures a partition according to information on components constituting the partition included in the instruction and, at the same time, changes the operation state of the operating system to the usual operation state.