There is provided a quantum dot light-emitting device including: a light-emitting layer containing a quantum dot luminescent material; and a metal-based particle assembly layer being a layer consisting of a particle assembly including 30 or more metal-based particles separated from each other and disposed in two-dimensions, said metal-based particles having an average particle diameter in a range of 200 to 1600 nm, an average height in a range of 55 to 500 nm, and an aspect ratio, as defined by a ratio of said average particle diameter to said average height, in a range of 1 to 8, wherein said metal-based particles that compose said metal-based particle assembly layer are disposed such that an average distance between adjacent metal-based particles may be in a range of 1 to 150 nm. The quantum dot light-emitting device provides enhanced emission via the metal-based particle assembly layer and thus presents high luminous efficiency.