The quantum double wave theory is applied to the time-dependent mesoscopic LC electric circuit with time-dependent capacitance and inductance. The averages and quantum fluctuations of the electric charge and magnetic flux (electric current) are given for a single time-dependent LC electric circuit. The obtained averages of the electric charge and magnetic flux satisfy the classical equation of motion. After making statistical average over the initial phases, the average and quantum fluctuation of every quantity reduce to that derived by the standard quantum mechanics. These results show that the double wave theory can be used to describe a single time-dependent mesoscopic electric circuit.