A light-emitting device including at least one light-emitting unit, a wavelength conversion adhesive layer, and a reflective protecting element is provided. The light-emitting unit has an upper surface and a lower surface opposite to each other. The light-emitting unit includes two electrode pads, and the two electrode pads are located on the lower surface. The wavelength conversion adhesive layer is disposed on the upper surface. The wavelength conversion adhesive layer includes a low-concentration fluorescent layer and a high-concentration fluorescent layer. The high-concentration fluorescent layer is located between the low-concentration fluorescent layer and the light-emitting unit. The width of the high-concentration fluorescent layer is WH. The width of the low-concentration fluorescent layer is WL. The width of the light-emitting unit is WE. The light-emitting device further satisfies the following inequalities: WE