To prevent misreading of barcodes and to allow accurate outputting of bar data even when an element is damaged or blurred, an optical information reading device containing a computation means 23a for adding widths of 6 elements containing a bar and a space that are adjacent within one character to derive respective patterns of 2- through n-element added widths and for converting each of the patterns of 2- through n-element added widths into the module number for one character to obtain the module numbers of the patterns of the 2- through n-element added widths; an extraction means 23b for narrowing down the target characters to extract a candidate character wherein the target character is that each module number of the 2- through n-element widths is an integer with an error equal to or less than 1; and a search means 23d for comparing the extracted candidate character, having the module numbers of the patterns of the 2- through n-element added widths with the expected value character for evaluating the candidate character to search for an expected value character with the strongest correlation to the candidate character.