A reproduction signal processing apparatus includes: a reproduction unit, an A/D converter for sampling a reproduction signal to obtain a multi-bit digital signal, a phase-locked loop controller for outputting a reproduction clock that is in phase with clock components included in the reproduction signal from an oscillator, a frequency divider for frequency-dividing the reproduction clock, an operation clock switching unit for selecting an operation clock, a filter for performing digital equalization, a filter coefficient learning unit for adaptively controlling the filter coefficients to minimize an equalization error, and an equalization error correcting unit for performing correction so as not to output an abnormal equalization error, thereby performing the adaptive equalization control with stability not only in the channel rate mode but also in the half rate mode that is introduced to suppress the power consumption.