In an optical bar-code reader, an optical scanner (11) optically scans a bar code (1) to obtain optical power of light reflected from white bars and black bars of the bar code (1), a differentiation unit (22) calculates a differential of the optical power to obtain a differential waveform, a dividing unit (23) divides the differential waveform into a positive waveform and a negative waveform, a bar-code correcting unit (24, 25) calculates correct widths of black bars in the bar code from the positive waveform and the negative waveform to create corrected bar-code data, and a converter (28) converts the corrected bar-code data into character data that is an array of numerals and letters.