1. A pattern recognition device comprising: a feature vector calculator configured to calculate a feature vector from input pattern; a model selecting unit configured to select, from models, one or more selection models whose distances from the feature vector are within a predetermined range, each of the models being represented by both an average vector of a pattern and a variance vector indicating variance of the pattern, and the average vector and the variance vector each having N dimensional components (N≧1); a correction vector calculator configured to calculate, for each of the selection models, a modified directional vector having the N dimensional components, a value of an n-th dimensional component (N≧n≧1) of the modified directional vector being obtained by subtracting a value of the n-th dimensional component of the variance vector multiplied by a predetermined coefficient from an absolute value of the n-th component of a different vector between the average vector and the feature vector to obtain a first value, and then multiplying the first value by a plus or minus sign identical to a sign of the n-th dimensional component of the difference vector, and further calculate a correction vector with respect to a vector obtained by superimposing the modified directional vectors; a feature vector correcting unit configured to correct the feature vector by using the correction vector; and a pattern recognition unit configured to perform recognition of the input pattern by using the feature vector corrected.