A 2D/3D switchable display device including a display panel and a switch unit is provided. The display panel includes a first substrate, a second substrate and a display unit located between the first and second substrates. The first substrate includes a first surface and a second surface opposite to the first surface, and the display unit is located above the first surface. The switch unit located on the second surface includes a third substrate, a first electrode layer, a second electrode layer and a switchable medium layer between the first and second electrode layers. The second electrode layer is located on the second surface, the first electrode layer is located on the third substrate, and the switchable medium layer and the third substrate are respectively located on two opposite surfaces of the first electrode layer. A manufacturing method of a 2D/3D switchable display device is also provided.