According to one embodiment, a method of manufacturing a display device, includes preparing a first substrate formed such that a first resin layer is formed on a first support substrate, and thereafter a display element portion and a mounting portion are formed above the first resin layer and a protection layer, which extends from an end portion of the first resin layer along the mounting portion onto the first support substrate, is disposed, preparing a second substrate formed such that a second resin layer is formed on a second support substrate, attaching the first substrate and the second substrate, and mounting a flexible printed circuit board, which is in a state in which the flexible printed circuit board is opposed to the protection layer, on the mounting portion.