According to one embodiment, a display device includes an insulating substrate, a wavelength conversion element, a light propagation layer including a light-path portion formed between the insulating substrate and the wavelength conversion element, wherein an area of a surface on the insulating substrate side is greater than an area of a surface on the wavelength conversion element side, and a non-light-path portion formed of a material having a refractive index less than the light-path portion, the light-path portion being sandwiched between the non-light-path portions, and a reflective film formed between the non-light-path portion and the wavelength conversion element.