FIG. 10 illustrates a life statistics table that is the management information for management of the lives of the SSDs 20. The life statistics table 550 illustrated in FIG. 10 includes SSD IDs 551, duration of use 552 representing time having elapsed from operation start time of the SSDs 20 identified by the SSD IDs 551, data storage ratios 553 each representing a maximum value of the storage ratios of the SSD 20 in the duration of use 552, remaining lives 554 of the SSDs 20, data volumes 555 of data to be written into the SSDs 20 in the duration of use 552, actual amounts of writing 556 that are volumes of data written actually into the SSDs 20 in the duration of use 552, and life consumption rates 557 indicating rates of decrease in the remaining lives 554 (rates of consumption of the remaining lives 554). The storage controller 10 calculates or measures the values 553 through 557 included in the life statistics table 550 for each specified period and sequentially adds the values to the life statistics table 550.

The remaining lives 554 have an initial value of 100% and the remaining life 554 that marks 0% indicates that the life of the SSD 20 has been exhausted. The remaining lives 554 are each calculated in accordance with an integrated value of the actual amount of writing 556, for instance. The life consumption rates 557 are each calculated as (actual amount of writing 556)/(data volume 555), for instance.