A field-effect transistor for nonvolatile memory holding use and a field-effect transistor for logical operation use are manufactured in the same structure on the same semiconductor substrate without separately providing manufacturing processes for the field-effect transistors for the two uses. Both a memory circuit and a logic circuit of a semiconductor integrated circuit are composed of n-channel and p-channel field-effect transistors including a memory holding material in a gate insulating structure. A logical operation state, a memory writing state and a nonvolatile memory holding state are electrically switched by controlling the level and application timing of a voltage to be applied between a gate conductor and a substrate region of the n-channel and p-channel field-effect transistors including the memory holding material in the gate insulating structure.