An automatic optical reading apparatus (1) having a light emitting section (26), a light receiving section (27) and an outside interface section (36). A first unit (2) houses at least one of the emitting section (26) and the receiving section (27) and a second unit (3) houses at least the outside interface section (36). The first unit (2) and the second unit (3) are mutually connectable in at least two different mutual orientations.