A data reproducing apparatus and method for improving data detection performance by adjusting decision levels used in a data detector. The data reproducing apparatus includes an equalizer which equalizes an input digital signal, a data detector which detects data from the output of the equalizer based on decision levels, and a level decision unit which detects levels corresponding to the decision levels used in the data detector from the output of the equalizer and feeds back corrected decision levels, which adaptively vary with the output level of the equalizer, to the data detector. Accordingly, the detection performance of the data detector is improved.