A digital slicing device is provided for making a numerical value determination with respect to an inputted modulated symbol so as to output a corresponding symbol. The digital slicing device includes a demodulating unit, a slicing unit and a re-modulating unit. The demodulating unit is for collecting at least two successive modulated symbols and for demodulating the two modulated symbols according to a modulation algorithm so as to generate two demodulated symbols. The slicing unit is for rounding the two demodulated symbols so as to generate two rounded demodulated symbols. The re-modulating unit is for re-modulating the two rounded demodulated symbols according to the modulation algorithm so as to generate two re-modulated symbols corresponding to the two modulated symbols. The two modulated symbols are generated simultaneously through conversion using the modulation algorithm.