1. An apparatus for recognizing voice, comprising: a feature vector extraction unit dividing an input voice signal into predetermined unit regions, and extracting feature vectors corresponding to each of the unit regions; a predicted node extraction unit extracting a list of second nodes whose travels to a first node corresponding to the extracted feature vectors are predicted, with reference to a network of one or more nodes; a single waveform similarity calculation unit calculating degrees of single waveform similarity of the first node and the second nodes of the list by substituting the extracted feature vectors into single waveform probability distributions that constitute voice signals corresponding to the second nodes; a multiple waveform similarity calculation unit calculating degrees of multiple waveform similarity by substituting the extracted feature vectors into multiple waveform probability distributions that constitute single waveform probability distributions usable to calculate the degrees of single waveform similarity in a preset range; and an output unit outputting a function-performing signal corresponding to a multiple waveform probability distribution that enables calculation of a highest of the calculated degrees of multiple waveform similarity.