A demultiplexing device that demultiplexes a reception signal into 2 N waves, N is a natural number equal to or larger than one, the demultiplexing device comprising: a reception low-pass-filter group including 2 N+1 -2 frequency-conversion and reception low-pass-filter units that each perform a frequency converting process and a low-pass filtering process for causing the reception signal to pass through a desired band, further perform downsampling to reduce a sampling rate to half of a data rate of an input signal, and output a processed signal, having the frequency- conversion and reception low-pass-filter units arranged in a tree with an N-stage configuration, dividing an output signal from each of 2 M frequency-conversion and reception low-pass-filter units arranged at an Mth stage into two, wherein 1≤M<N and inputting the divided signals to two different frequency-conversion and reception low-pass-filter units at a subsequent stage, respectively; and a reception channel-filter group including 2 N reception channel-filter units that waveform-shape signals from the frequency-conversion and reception low-pass-filter units according to a desired frequency characteristic to output the waveform-shaped signals and are arranged to connect to 2 N frequency-conversion and reception low-pass-filter units at an Nth stage in a one-to-one relation; characterized by that it further comprises a filter-bank control unit that generates a clock control signal for controlling clock supply to frequency-conversion and reception low-pass-filter units and reception channel-filter units corresponding to a signal passage band, based on channel information; and a reception-clock supply unit that supplies a clock to frequency-conversion and reception low-pass-filter units and reception channel-filter units corresponding to the signal passage band, based on the clock control signal, wherein the frequency characteristic satisfying, when the frequency characteristic is represented as A(f) and a minimum channel width is Fc, the A(f) is defined in equations, and, where f is a frequency, Bw is a minimum signal bandwidth that falls within the Fc, A f = 1.0 f ≤ 0.5 Bw A f = 0.0 f > Fc − 0.5 Bw A f + A Fc − f = 1.0 0.5 Bw < f ≤ Fc − 0.5 Bw a reception low-pass-filter group including 2 N+1 -2 frequency-conversion and reception low-pass-filter units that each perform a frequency converting process and a low-pass filtering process for causing the reception signal to pass through a desired band, further perform downsampling to reduce a sampling rate to half of a data rate of an input signal, and output a processed signal, having the frequency- conversion and reception low-pass-filter units arranged in a tree with an N-stage configuration, dividing an output signal from each of 2 M frequency-conversion and reception low-pass-filter units arranged at an Mth stage into two, wherein 1≤M<N and inputting the divided signals to two different frequency-conversion and reception low-pass-filter units at a subsequent stage, respectively; and a reception channel-filter group including 2 N reception channel-filter units that waveform-shape signals from the frequency-conversion and reception low-pass-filter units according to a desired frequency characteristic to output the waveform-shaped signals and are arranged to connect to 2 N frequency-conversion and reception low-pass-filter units at an Nth stage in a one-to-one relation; characterized by that it further comprises a filter-bank control unit that generates a clock control signal for controlling clock supply to frequency-conversion and reception low-pass-filter units and reception channel-filter units corresponding to a signal passage band, based on channel information; and a reception-clock supply unit that supplies a clock to frequency-conversion and reception low-pass-filter units and reception channel-filter units corresponding to the signal passage band, based on the clock control signal, wherein the frequency characteristic satisfying, when the frequency characteristic is represented as A(f) and a minimum channel width is Fc, the A(f) is defined in equations, and, where f is a frequency, Bw is a minimum signal bandwidth that falls within the Fc, A f = 1.0 f ≤ 0.5 Bw A f = 0.0 f > Fc − 0.5 Bw A f + A Fc − f = 1.0 0.5 Bw < f ≤ Fc − 0.5 Bw