When a write & auto precharge command is input into a chip, signals CPSRX and AUTPL are at "H". After finishing a column operation, the level of the signal CPSRX shift to "L". When CPSRX="L" and AUTPL="H", if a signal CSLCK is at "H", an auto precharge enable signal AUTPE is at "H". The signal AUTPE is at "H" when the signal CSLCK is at "H", and does not depend upon the leading edge of an external clock VCLK. Since auto precharge is executed from the time a column select line CSL is activated, the time the potential of a selected word line is shifted to a non-selection level can be kept constant irrespective of the frequency of the external clock.