PURPOSE: To obtain a parallel waveform equalizer capable of reducing processing time required for waveform equalization processing in an equalizer which performs the adaptive equalization of waveform distortion such as a ghost, etc.

CONSTITUTION: A distorted input signal 1 is separated to four FIFOs. The output of the FIFOs are subtracted by the contents of ROMs 9-12, and error signals are outputted to RAMs 25-28. The error signals are compared at comparators 21-24, and an error is detected when a sample with a value other than zero exists. and delay quantity is activated. When only the sample with a value zero exists, the comparators 21-24 activates a ROM 48 provided with already decided delay quantity and from which a single weight impulse is outputted. RAMs 33-36 are memory to change a weight coefficient decided by multiplying a floating point constant from a ROM 47 at the RAMs 25-28, which effectively reduce the ghost.