Multi-screen display device for reducing a non-display area between display panels, and manufacturing method thereof

A display device includes: first and second display panels adjacent to each other along one direction, wherein: each of the first and second display panels includes a substrate, and a display portion on the substrate and includes a plurality of pixels including a pixel circuit layer on the substrate, at least one transistor, a display element layer on the pixel circuit layer, and at least one light emitting element emitting light; the substrate of the first display panel and the substrate of the second display panel are engaged with each other in a plan view and a cross-sectional view; the display portion of the first display panel and the display portion of the second display panel are engaged with each other in a plan view and a cross-sectional view; and a boundary between the display portion of the first display panel and the display portion of the second display panel.