PURPOSE: To correctly reproduce codes by providing this digital radio wave demodulating circuit with a switch for connecting a reference voltage source to a capacitor when a voltage value exceeds a regulated value.

CONSTITUTION: When an adjacent channel wave is inputted and its level is increased, DC voltage values outputted from low pass filters(LPFs) 51, 52 are shifted up and down in accordance with a leakage value into the band of a required channel. When the voltage value exceeds the regulated range, an identification circuit 11 changes over a switch 12 so as to connect the capacitor C to the reference voltage source 13 to suppress the generation of a potential difference between both terminals of the capacitor 6. When the desired channel wave arrives in this state, the DC voltage values outputted from the LPFs 51, 52 are led into the regulated range and the circuit 11 changes over the switch 12 again to connect the LPF 52 to the capacitor 6 and drives a code reproducing circuit 7 and a clock reproducing circuit 8.