In a portable electronic apparatus, a second keyboard to be manipulated with a right hand is joined to a first keyboard unit including a first keyboard to be manipulated with a left hand so that the second keyboard can be turned down. A display unit having a built-in liquid crystal display is joined to the first keyboard unit so that the display unit can be tuned down. When the display unit is turned down, the display unit engages with the second keyboard unit that is turned down. When all the parts of the electronic apparatus are closed, the electronic apparatus serves as a CD player of a CD jacket size. When the display unit is opened, the electronic apparatus has not only the capability of a DVD player but also the capability of a simple personal computer. When all the parts are left open, the electronic apparatus serves as a personal computer having a full keyboard.