To use an adaptive equalizing circuit for a reproducing device without tracking control.

A reproducing signal to be supplied to an input terminal 20 is supplied to plural unit delay means 21-24 connected in series, and input and output end signals are supplied to weighting means 25-29, respectively. Moreover, the reproducing signal to be supplied to the input terminal 20 is supplied to arithmetic circuitry 30 to obtain weighting coefficients C1-C5. Then, the respective signals each the unit delay means 21-24 are weighted and are summed by an adder 31 to equalize the reproducing signal and taken out of the output terminal 32. At the same time, the arithmetic circuitry 30 controls so that calculations of the weighting coefficients C1-C5 are performed only when an envelope value of the reproducing signal is not less than a prescribed value and the phase is locked to the reproducing signal, and the coefficients of the weighting means 25-29 are changed according to the obtained weighting coefficients C1-C5.