PURPOSE: To use the semiconductor integrated circuit with both the higher and lower frequencies in a semiconductor integrated circuit incorporating a liquid crystal oscillation circuit to be used for microcomputers and to suppress the consumption current even though oscillated in the lower frequency.

CONSTITUTION: In a semiconductor integrated circuit 17 having the liquid crystal oscillation circuit, a feedback resistance 12 is connected in parallel to a CMOS invertor 11. A tristate invertor 13 is connected in parallel to the CMOS invertor 11 and a signal SG is inputted in the invertor 13. Further, an output signal CLK is outputted from the output end of the CMOS invertor. By making the signal SG high or low level, the tristate invertor 13 is turned on or off.