Abstract: Bar codes and auxiliary characters representative of the contents of the bar codes are printed on an article which is limited with respect to the available space in distinguishably recognizable and superposed relations. By selecting appropriately the lightness of the auxiliary characters, reflected light resulting from scanning of the bar code is converted into an electrical signal which is subsequently converted into a binary signal with the signal components due to the auxiliary characters being neglected, to thereby extract only the signal originating in the bar code. A bar code reader is provided which comprises an A/D converter for compensating the output of bar code detection due to the character pattern superposed on the bar code.