Disclosed are a multimedia device including a flexible display and controlling method thereof. The present invention includes a guide bar, a flexible display configured to be rolled up on an outer circumference of the guide bar, the flexible display having a first region rolled up on the outer circumference of the guide bar and a second region not rolled up on the outer circumference of the guide bar, a receiving unit configured to receive a content and metadata corresponding to the content from a source device, and a control unit adjusting a vertical width of the second region of the flexible display in accordance with a preset condition.