A storage controller that can maintain its performance and reduce power consumption and thereby realize large capacity and low power consumption, and a method for controlling such a storage controller are provided. The storage controller includes a plurality of nonvolatile memory modules having a plurality of nonvolatile memory chips for storing data from a host computer, and a nonvolatile memory control unit for controlling data input to and output from the host computer by controlling a power source for the nonvolatile memory modules. When reading or writing data from or to a designated nonvolatile memory module at a specified time in response to a data read/write request from the host computer, the nonvolatile memory control unit controls the power source for only the designated nonvolatile memory module to be turned on.