A sense amplifier controlling circuit for controlling a sense amplifier in a semiconductor memory, which amplifies differential electric potential of a pair of bit lines to which memory cells are connected by sequentially operating a CMOS flip-flop and a preamplifier performing an amplification operation different from each other, controls the sense amplifier, and activate the preamplifier at an early operation stage of the CMOS flip-flop and the preamplifier independently of activation of the CMOS flip-flop during the amplification operation of the CMOS flip-flop.