Abstract: An auto player technique is provided in a recording/reproducing apparatus storing a plurality of disks, wherein size of the apparatus can be reduced in height and width and positioning accuracy can be increased. A pair of tray stockers are disposed right and left. A lifter transporting the tray in a vertical direction is disposed behind the tray stockers. The lifter includes a tray extracting mechanism selectively extracting disks from the tray stockers. The tray extracting mechanism simultaneously engages with two trays disposed at the same height of the right and left tray stockers when extracting trays. A recording/reproducing device is disposed below the lifter. A drive mechanism engages with the recording/reproducing device to shift it in a right and left direction. A lock mechanism is provided to engage with the recording/reproducing device when the drive mechanism is disengaged from the recording/reproducing device.