A method for reducing a memory map table search time when employing a semiconductor memory device as a temporary memory of large capacity storage device, and a semiconductor memory device therefore, are provided. A MAP RAM is prepared for storing map table data related to the nonvolatile memory area in the volatile memory area. At an initial power-up operation, it is determined whether a logical address is searched for from the map table data while the map table data existing in a map storage area of the nonvolatile memory area is loaded into the MAP RAM. A physical address corresponding to the logical address is provided as an output, when the logical address is searched for. Search time for a memory map table is reduced and read performance in a high speed map information search is increased.