The present invention provides a head array unit in which a plurality of head members is easily aligned on an alignment member with a simple structure and a method for manufacturing the head array unit, and an image forming apparatus including the head array unit. The head array unit includes a head unit. The head unit includes a head member, a head member retainer, and an alignment member. The head member includes a plurality of nozzles and is configured to eject liquid droplets. The head member retainer, on which the head member is disposed and fixed thereto, includes a reference hole for aligning the head unit relative to the alignment member. The alignment member includes an opening formed at a location associated with the reference hole and relatively larger than the reference hole. The head member may be directly aligned and fixed on the alignment member.