In a storage apparatus, a calculation unit calculates first power consumption by adding the power consumption of a first storage device not in use to the total power consumption of a plurality of storage devices in operation, and calculates second power consumption by adding the power consumption of a second storage device not in use to the total power consumption of the plurality of storage devices in operation, and subtracting therefrom the power consumption of one of the plurality of storage devices in operation, from which data is movable to the second storage device. A determination unit determines to activate the first storage device when the second power consumption is not lower than the first power consumption, and determines to activate, the second storage device when the second power consumption is lower than the first power consumption.