Provided is a door opening/closing device unit which is capable of preventing shifting of the mounting position of a connecting rod to door opening/closing devices and facilitating the mounting work. The door opening/closing device unit has at least one support member 8 mountable on a housing 1, a pair of door opening/closing devices 4 for moving a door 2 relative to the housing 1 and a connecting member 5 for connecting the door opening/closing devices so as to synchronize operations of the door opening/closing devices. First the support member 8 is mounted on the housing 1, and then, at least one of the paired door opening/closing devices 4 connected by the connecting member 5 is mounted on the one support member 8.