Provided is a substrate for a light-emitting device having good light emitting efficiency and light-emitting device using the substrate. A light transparent substrate 10 is layered with a first layer 30 having a refractive index higher than that of the light transparent substrate 10 and a s second layer 40 having a refractive index lower than that of the first layer. The refractive index of the first layer 30 is set to be 1.35 times as high as that of the second layer 40. With this layer structure, in an emitting layer of the light-emitting device, a wave front of a spherical wave form exited from a point light source in the front direction is converted into that of a plane wave form, and exited outside the substrate at a high efficiency.