A semiconductor memory device includes a clock inputting unit configured to receive a system clock and a data clock, a clock dividing unit configured to divide a frequency of the data clock to generate a data division clock and determining a phase of the data division clock according to a division control signal, a phase dividing unit configured to generate a plurality of multiple-phase data division clocks each having a predetermined phase difference according to the data division clock, and a first phase detecting unit configured to detect a phase of the system clock based on a predetermined selection clock among the multiple-phase data division clocks, and generate the division control signal according to the detection result.