A digital multimedia device capable of functioning as both a portable multimedia player (PMP) and a notebook computer is provided. The digital multimedia device includes: a computer unit including a body, a first processor included in the body to operate a first operating system (OS), a first display unit for displaying image information processed by the first processor, and a first input unit; a PMP unit including a second processor to operate a second operating system, a hard disk drive (HDD) for storing programs and data, a second display unit for displaying image information processed by the second processor, and a second input unit; and a docking unit disposed in the computer unit and the PMP unit for docking the PMP unit to the computer unit, wherein, when the PMP unit is docked with the computer unit, the computer unit shares the HDD with the PMP unit to perform processing operations, and the PMP unit operates independently or in association with the computer unit.