6. An optical information reading method, comprising: adding of 2 elements through n elements, the 2 elements containing a bar and a space that are adjacent within one character, wherein n is greater than 2, the n greater than 2 elements containing two or more bars and one or more spaces and one or more bars and two or more spaces that are adjacent within one character to obtain respective 2- through n-element added widths; converting each of the obtained 2- through n-element added widths into a module number with respect to one character to obtain an actual measurement value of the module number of the 2- through n-element added widths; extracting a candidate character by narrowing down target characters wherein each of errors between the actual measurement value and an ideal value of the module number for all the 1-element and the obtained 2- through n-element added widths is equal to or less than 1, to extract candidate characters; and searching the one candidate character having the minimum of the summed errors as the readout decode result.
6. An optical information reading method, comprising: adding of 2 elements through n elements, the 2 elements containing a bar and a space that are adjacent within one character, wherein n is greater than 2, the n greater than 2 elements containing two or more bars and one or more spaces and one or more bars and two or more spaces that are adjacent within one character to obtain respective 2- through n-element added widths; converting each of the obtained 2- through n-element added widths into a module number with respect to one character to obtain an actual measurement value of the module number of the 2- through n-element added widths; extracting a candidate character by narrowing down target characters wherein each of errors between the actual measurement value and an ideal value of the module number for all the 1-element and the obtained 2- through n-element added widths is equal to or less than 1, to extract candidate characters; and searching the one candidate character having the minimum of the summed errors as the readout decode result. 7. The optical information reading method according to claim 6 wherein the adding includes adding the widths of the elements containing the character bars and the spaces of the characters before and after the target character when obtaining each of the 2- through n-element added widths of the target character.