A wavelength selection switch system includes a wavelength selection switch including an input port and an output port, a nonvolatile memory in which configuration information for controlling an operation of the wavelength selection switch is stored, a high-speed memory in which reading and writing can be performed at a higher speed than in the nonvolatile memory and that stores a copy of the configuration information stored in the nonvolatile memory, and a control unit that controls an operation of the wavelength selection switch based on the configuration information read from the high-speed memory, wherein the control unit periodically reads the configuration information stored in the nonvolatile memory and writes a copy of the read configuration information to the high-speed memory.