A continuous speech recognition system utilizes a format memory (14) which specifies a sequence of word sets and a plurality of words, or reference patterns, which may be included in each word set. The input pattern sequence is divided into all possible partial patterns having start points p and end points q, and each of these partial patterns is compared with all reference patterns to derive elementary similarity measures. The elementary similarity measures for each combination of a partial pattern and a permitted word in a word set under the specified format are then examined to determine the optimum input pattern segmentation points and corresponding sequence of reference patterns which will yield a maximum similarity result. The maximum similarity is represented by ##EQU1## where S(p(x-1), p(x),n(x)) indicates the degree of similarity between an input partial pattern having a start point p(x-1) and an n point p(x) and a reference word unit n(x) within a word set f.sub.x, and K represents the number of word sets permitted according to the specified format.