A semiconductor synchronous dynamic random access memory (SDRAM) device capable of correcting bits having a low error rate in a Pause Refresh Tail distribution and of reducing a data holding current by lengthening a refresh period so that the refresh period exceeds a period for a Pause Refresh real power. The semiconductor memory device is made up of a 16-bit SDRAM having a Hamming Code and including an ECC (Error Correcting Code) circuit made up of an encoding circuit controlled by a first test signal to output a parity bit corresponding to an information bit, a decoding circuit controlled by second test signal to output an error location detecting signal indicating an error bit in codeword, and an error correcting circuit controlled by a third test signal to input an error location detecting signal and to output an error bit in a reverse manner.