An interference wave suppressing apparatus comprising: a demultiplexing unit configured to demultiplex a reception signal into demultiplexed signals having predetermined bandwidth; an interference-wave detecting unit configured to determine, for each of the demultiplexed signals, based on a power value of the demultiplexed signal, whether an interference wave is present; an interference-wave suppressing unit configured to change a signal value of the demultiplexed signal, in which the interference-wave detecting unit determines that an interference wave is present, to a value equal to or smaller than a predetermined value, output the demultiplexed signal after the change, and also output the demultiplexed signal, in which the interference-wave detecting unit determines that an interference wave is absent; and a multiplexing unit configured to output a multiplexed signal obtained by multiplexing signals output from the interference-wave suppressing unit; characterized in that the reception signal is demultiplexed into the demultiplexed signals according to demultiplexing processing at N (N is an integer equal to or larger than 1) stages, the demultiplexing unit includes frequency conversion filter units (71-1, 71-2, 72-1 to 72-4, 73-1 to 73-8) configured to perform frequency conversion to shift a center frequency of an input signal by a predetermined frequency, extract a signal in a predetermined band from the signal after the frequency conversion, perform down-sampling processing for reducing a sampling frequency of the extracted signal, and output the signal after the down-sampling, the demultiplexing unit including a pair of the frequency conversion filter units at a first stage and including, at a second and subsequent stages, the frequency conversion filter units twice as many as the frequency conversion filter units at the preceding stage, at the second and subsequent stages, the demultiplexing unit inputs, to a pair of the frequency conversion filter units at a same stage, a same signal output from the same frequency conversion filter unit at the preceding stage, and in the frequency conversion filter units to which the same signal is input, the demultiplexing unit sets frequencies to be shifted by the frequency conversion to values different from each other. a demultiplexing unit configured to demultiplex a reception signal into demultiplexed signals having predetermined bandwidth; an interference-wave detecting unit configured to determine, for each of the demultiplexed signals, based on a power value of the demultiplexed signal, whether an interference wave is present; an interference-wave suppressing unit configured to change a signal value of the demultiplexed signal, in which the interference-wave detecting unit determines that an interference wave is present, to a value equal to or smaller than a predetermined value, output the demultiplexed signal after the change, and also output the demultiplexed signal, in which the interference-wave detecting unit determines that an interference wave is absent; and a multiplexing unit configured to output a multiplexed signal obtained by multiplexing signals output from the interference-wave suppressing unit; characterized in that the reception signal is demultiplexed into the demultiplexed signals according to demultiplexing processing at N (N is an integer equal to or larger than 1) stages, the demultiplexing unit includes frequency conversion filter units (71-1, 71-2, 72-1 to 72-4, 73-1 to 73-8) configured to perform frequency conversion to shift a center frequency of an input signal by a predetermined frequency, extract a signal in a predetermined band from the signal after the frequency conversion, perform down-sampling processing for reducing a sampling frequency of the extracted signal, and output the signal after the down-sampling, the demultiplexing unit including a pair of the frequency conversion filter units at a first stage and including, at a second and subsequent stages, the frequency conversion filter units twice as many as the frequency conversion filter units at the preceding stage, at the second and subsequent stages, the demultiplexing unit inputs, to a pair of the frequency conversion filter units at a same stage, a same signal output from the same frequency conversion filter unit at the preceding stage, and in the frequency conversion filter units to which the same signal is input, the demultiplexing unit sets frequencies to be shifted by the frequency conversion to values different from each other.