Abstract: Comprises a pre-orientating device (2) suitable for placing a plurality of articles (50) in the vertical position, randomly head up or head down, on a conveyor (1); detection means (3) for detecting the articles (50) that are in at least one of said positions, head up or head down, on conveyor (1); and ejection means (4) for selectively ejecting from conveyor (1) those articles (50) that are in one of said undesired head up or head down positions, on the basis on said detection. It optionally comprises reloading means (15) suitable for picking up those articles (50) that are ejected from conveyor (1) by ejection means (4), conveying them and loading them again into pre-orientating device (2).