A flexible rack member has a substantially V-shaped cam portion formed therein. There is a substantially U-shaped guide slit formed on a wall of a housing. A support bar projected from a reproducing unit is formed so as to fit in a cam portion through the guide slit. Further, tray racks are formed on respective side faces of each tray. Joint pins mounted on both end portions of the rack member are guided by a guide groove formed on each tray while being in mesh therewith. As a result, by moving the rack member between the trays, an up-and-down movement of the reproducing unit, a movement of the reproducing unit between the trays, and an opening and closing of each tray can be carried out successively. Additionally, there is a tray gear member as the only drive source, and a contact portion formed on the guide groove is a key to switch each operation. The described arrangement provides an inexpensive disk reproducing device which enables the operation to be switched with an accurate timing.