A light-emitting device (1, 21, 31, 41, 51, 61) comprising: a supporting substrate; an organic electroluminescent element disposed on the supporting substrate; a sealing substrate for sealing the organic electroluminescent element, comprising a convex portion protruding toward the organic electroluminescent element; and a heat conducting member that is provided between the organic electroluminescent element and the convex portion, wherein the organic electroluminescent element is composed of an anode (11, 12), a cathode (11, 12) and a light-emitting layer provided between the anode (11, 12) and the cathode (11, 12), the anode (11, 12) has optical transparency, and the cathode (11, 12) that reflects light emitted from the light-emitting layer on a cathode (11, 12) toward the anode (11, 12) is formed of a material having a high visible-light reflectivity, wherein the organic electroluminescent element and the convex portion are attached through the heat conducting member, wherein the heat conducting member is provided so as to contact with both the convex portion and the organic electroluminescent element, and the heat conducting member includes a filler, and the filler has the highest heat conductivity among materials included in the heat conducting member, the filler being formed of at least one material selected from the group consisting of aluminum oxide, aluminum nitride, beryllium oxide, boron nitride, and aluminum, copper, silver and any alloys thereof, and sintered materials comprising carbon or silicon, wherein a part or whole of the convex portion is overlapped with the organic electroluminescent element, and an area of an overlapped region of the convex portion and the organic electroluminescent element is smaller than an area of the organic electroluminescent element, as viewed from a thickness direction of the supporting substrate. a supporting substrate; an organic electroluminescent element disposed on the supporting substrate; a sealing substrate for sealing the organic electroluminescent element, comprising a convex portion protruding toward the organic electroluminescent element; and a heat conducting member that is provided between the organic electroluminescent element and the convex portion, wherein the organic electroluminescent element is composed of an anode (11, 12), a cathode (11, 12) and a light-emitting layer provided between the anode (11, 12) and the cathode (11, 12), the anode (11, 12) has optical transparency, and the cathode (11, 12) that reflects light emitted from the light-emitting layer on a cathode (11, 12) toward the anode (11, 12) is formed of a material having a high visible-light reflectivity, wherein the organic electroluminescent element and the convex portion are attached through the heat conducting member, wherein the heat conducting member is provided so as to contact with both the convex portion and the organic electroluminescent element, and the heat conducting member includes a filler, and the filler has the highest heat conductivity among materials included in the heat conducting member, the filler being formed of at least one material selected from the group consisting of aluminum oxide, aluminum nitride, beryllium oxide, boron nitride, and aluminum, copper, silver and any alloys thereof, and sintered materials comprising carbon or silicon, wherein a part or whole of the convex portion is overlapped with the organic electroluminescent element, and an area of an overlapped region of the convex portion and the organic electroluminescent element is smaller than an area of the organic electroluminescent element, as viewed from a thickness direction of the supporting substrate.