A liquid ejecting head, a liquid jet head unit and their manufacturing method and a liquid jet apparatus

A method for fabricating a liquid ejecting head unit including a liquid ejecting head having a nozzle line with a plurality of nozzle openings which are arranged in parallel, and a base plate on which the liquid ejecting head is mounted, the method includes: forming a second reference which is positioned to a first reference installed on the base plate, and a positioning adjusting hole on a positioning plate by a photolithographic method; attaching the positioning plate to the liquid ejecting head in such a way that the positioning adjusting hole and the nozzle openings have a predetermined arrangement; and fixing the liquid ejecting head to the base plate in a state in which the first reference and the second reference are positioned.