A junction device for connecting two ends of at least one longitudinal conveyor belt includes at least a first junction plate and a second junction plate which are configured to each cover a distinct side of the ends of the conveyor belt, a fastening device for fastening said junction plates together, and a removable spacer which is suited to be interposed between the wings of the first pair of wings formed by the junction plates, such that the centring hole of the spacer is offset from the junction plane, to free the space delimited between the second pair of wings.