Easy and fast memory access with correcting defects is to be realized. In a spare memory in a semiconductor memory device, a redundant memory cell array that stores the number of correcting defects is provided. When a signal from the outside is received, the signal is switched to the redundant memory cell array, and the number of correcting defects is judged. Then, based on the result of the judgment, it is determined the judgment of a defective memory cell is continued or the judgment is finished to write data to a main memory cell. By providing the redundant memory cell array that stores the number of correcting defects, a state of correcting defects can be observed fast in such a manner.