A foldable display device includes a holding structure and a flexible display panel. The holding structure includes a housing, a first supporting stage, a second supporting stage, a supporting element, and a first flexible element. A third portion of the housing is pivotally connected to a first portion and a second portion of the housing. The third portion of the housing has an accommodating space. The first supporting stage is located on the first portion of the housing. The second supporting stage is located on the second portion of the housing. A gap is formed between the portion of the second supporting stage and the portion of the first supporting stage. The supporting element is located in the accommodating space. Two ends of the first flexible element are respectively connected to the supporting element and the third portion of the housing.