1. A character recognition device for use with a medium on which a character string is printed, the character recognition device comprising: an image reader structured to capture the character string on the medium as image data; an image memory structured to store the image which is read by said image reader; and a data processor structured to segment the character string from said image data stored in said image memory and segmenting characters from said character string for character recognition; wherein said data processor comprises: a character segmenting unit structured to detect boundary positions of neighboring characters in said character string and segment each character; and said character segmenting unit comprises: a boundary search range setting unit structured to set a range to search boundary position of neighboring characters in said character string and a boundary position setting unit structured to set a boundary position of characters by using a discriminant analysis method within said search range which has been set; and said boundary position setting unit is structured to divide a projection to said boundary search range by a predetermined width into two regions, calculate the within-region variance in each region, the between-region variance, and the variance ratio between the within-region variance and the between-region variance, and set a segmentation position of characters based on said calculated variance ratio.