A sense amplifier overdriving circuit includes a first voltage driver which supplies an internal voltage from an internal voltage terminal to a sense amplifier in response to a first enabling signal, a logic unit which logically operates a block select signal for selection of a cell block and a second enabling signal enabled for a predetermined time after enabling of the first enabling signal, and outputs the resultant signal, and a second voltage driver which supplies an external voltage to the internal voltage terminal in response to the signal output from the logic unit.