A semiconductor integrated circuit device which includes a logical circuit containing a MIS transistor on a semiconductor substrate, a control circuit for controlling a threshold voltage of the MIS transistor in the logical circuit, an oscillation circuit containing a MIS transistor on the semiconductor substrate, and a buffer circuit, the control circuit compares the frequency of the oscillation output and frequency of a clock signal to output a first control signal, the first control signal controls a threshold voltage of the MIS transistor of the oscillation circuit, and the buffer circuit is inputted with the first control signal to output a second control signal corresponding to the first control signal, the second control signal controlling the threshold voltage of the MIS transistor of the logical circuit.