PURPOSE: To simplify control, to reduce the size of hardware and to remove an interference in a symbol waveform by forming subtractors, an adder, a deciding unit, a pattern checking circuit, and plural adaptive filters.

CONSTITUTION: A receiving signal including an inter-code interference is supplied from a transmission line to an input terminal 1 and inputted to a subtractor 2 and a difference signal (receiving signal including a residual inter-code interference) obtained by subtracting a false inter-code interference outputted from the adder 19 from the receiving signal is outputted from the subtractor 2. The difference signal is supplied to the deciding unit 3, the pattern checking circuit 12, the adaptive filter, etc., to find out the sum or difference between the current sample value and a sample value obtained before iTsec and to extract the residual inter-code interference. A factor is updated by using the sum or difference as an error signal only when the residual inter-code interference is correctly extracted. Consequently, the control can be simplified, the size of the hardware can be reduced and the interference in a symbol waveform can be removed.