A door interlock unit to be used with a disk recording/reproducing apparatus having a disk tray and a door through which the disk tray moves in and out of the disk recording/reproducing apparatus, the door interlock unit including a restricting member to restrict the door from being opened in response to the disk tray being positioned inside the disk recording/reproducing apparatus, wherein the restricting member is engaged by the disk tray entering the disk recording/reproducing apparatus; and/or a restricting member to restrict the disk tray from moving toward a disk loading position in the disk recording/reproducing apparatus in response to the door being in an open position; wherein the restricting member is coupled to the door so as to be engaged and disengaged by the door opening and closing, respectively.