A semiconductor integrated circuit device includes a functional circuit part that includes a plurality of field effect transistors, a mode control circuit that receives a first control signal and that generates a second control signal that is used to change a logic state of the functional circuit part, an output control circuit that receives an output signal of the functional circuit part and controls output of the output signal, and a control circuit that receives the second control signal and that generates a third control signal to the output control circuit. During a time period when the functional circuit part changes a logic state according to the second control. signal, the output control circuit inverts the output signal of the functional circuit part according to the third control signal.