An evaluation method is proposed to evaluate reliability of a nonvolatile memory in a semiconductor storage device with respect to data writing and data reading. While power is being supplied to the semiconductor storage device, a test program and the control program are written in a storage unit of the semiconductor storage device. The test program being written to control execution of an evaluation test performed for evaluating the reliability of the nonvolatile memory and generate a simulated access command identical to an access command input externally for accessing the nonvolatile memory. Access to the nonvolatile memory is controlled according to the test program and control program in the storage unit.