A semiconductor memory device, to which a plurality of command signals are supplied in synchronous with a clock, comprises a plurality of input circuits, having a sampling unit for inputting said command signals and said clock and sampling said command signals in synchronous with said clock, and an output unit for outputting said sampled command signals; a command decoder for receiving the command signals output by said plurality of input circuits, decoding said plurality of command signals and generating a corresponding control signal; a memory element, which implements a variety of operational modes in response to said control signals; an output timing signal generator circuit, having a circuit architecture equivalent to at least the sampling unit of said input circuit, for sampling a predetermined signal level in synchronous with said clock, and for generating an output timing signal based on the timing of the operational delay time of said sampling unit; and wherein said input circuit outputs said sampled command signals in response to said output timing signal.