In a semiconductor integrated circuit which contains, on the same chip, at least one logic circuit operating with a positive potential power and at least one logic circuit operating with a negative potential power, a level converter circuit is inserted between above logic circuits and is constituted of two series circuits each consisting of a P-channel MOSFET and an N-channel MOSFET connected in series between power lines supplied with the positive potential power and the negative potential power, and wirings to form a flip-flop circuit with each one MOSFET in respective series circuits.