Provided is a performance information management system which includes a target apparatus having a plurality of components as monitoring targets and a management computer for managing the target apparatus and which manages performance information of the target apparatus with the management computer, wherein the target apparatus is capable of acquiring performance information for each monitoring target, and the management computer is configured to: allocate an initial storage area of which capacity differs for each monitoring target to each of the monitoring targets; detect depletion of a storage area allocated to a monitoring target when attempting to store the performance information of the monitoring target to the storage area; additionally allocate a consecutive storage area with a prescribed capacity to the monitoring target with the depleted storage area; and store the performance information of the monitoring target in the additionally-allocated storage area.
