A slot-in disk drive device and a method thereof. The device includes a drive unit for providing power to move a slider. A loading unit moving with the slider drives a loading stick to push a disc into the device. The slider has a sliding slot. An ejecting unit with a bar-linkage mechanism has one end driven by the sliding slot, and the other end for rotating an ejecting bar to guide or push the disc out. A receiving unit has a receiving bar for guiding the disc, and has a positioning bar disposed between the loading unit and the ejecting unit. A sensing unit includes a plurality of sensing switches respectively disposed near the moving paths of the receiving bar, the ejecting unit and the positioning bar. The drive unit is enabled to load the disk is determined according to the order of actuating the switches.