To provide a portable display device which has portability and permits changing of a screen size.

The portable display device has a display screen housed in a display screen housing equipped with an interconnection module docking port. The interconnection module docking port is coupled with an interconnection module which connects to the display screen housing to form one housing. The interconnection module is equipped with an input receptacle constituted to be coupled to a display source. The interconnection module and the display device include an electronic circuit for sending display output from the display source to the display screen so that the display output is displayed on the display screen.