A high-performance differential latch circuit which includes a differential amplifier circuit comprised of an NMOS transistor (27) serving as a constant current source, PMOS transistors (3, 4) and NMOS transistors (23,24), a latch circuit comprised of NMOS transistors (25, 26), and a switch circuit comprised of NMOS transistors (21,22,28) for alternately operating the differential amplifying function and latch function, the transistor (27) serving as the constant current source having a drain terminal directly connected to the transistors (23,24) and a source terminal directly connected to a ground voltage (2), whereby the differential latch circuit differentially amplifies the signals without the loss of the constant current source function during the differential amplification.