A multi-screen display device includes a plurality of display screens and a prism-structured optical element disposed between two adjacent display screens. The prism-structured optical element includes a substrate and a plurality of prisms arranged in a predetermined direction on the substrate. The substrate includes a first region and a second region adjacent to each other, and the lengths of the first and second regions in the predetermined direction are respectively La and Lb, and La≥Lb. The prism includes a plurality of first and second prisms in the first and second regions respectively. Each first and second prism has internal angles θa1, θa2 and internal angles θb1 and θb2 adjacent to the substrate. The inner angle θa1 is between the inner angle θa2 and the second region, and θa1