A cover (1, 1A) for a light emitter having one or more light emitting devices, comprising: a glass plate having an upper face, a lower face, and a peripheral side surface; a frame (20, 20A) having an opening smaller than the glass plate; and a low melting glass having a lower melting point than the glass plate, the glass plate being sealed to the frame (20, 20A) with the low melting glass to close the opening, wherein the frame (20, 20A) has an encircling step (30, 30A) formed on a side thereof to which the glass plate is sealed, wherein the encircling step (30, 30A) includes: a placement face situated at a recessed position relative to an upper surface of the frame (20, 20A), the placement face being in contact with a perimeter of the lower face of the glass plate to have the glass plate placed thereon; and a wall face (32, 32A) connecting the upper surface of the frame (20, 20A) and the placement face, wherein the wall face (32, 32A) includes a plurality of inner sides forming the perimeter of the opening, wherein the wall face (32, 32A) includes first wall faces situated at opposite ends of each inner side of the encircling step (30, 30A) and a second wall face (32b, 32c) situated between the first wall faces, and wherein gaps between the first wall faces and the peripheral side surface of the glass plate and a gap between the second wall face (32b, 32c) and the peripheral side surface of the glass plate are filled with the low melting glass the cover (1, 1A) being characterized in that: the frame (20, 20A) is made of metal; and that the second wall face (32b, 32c) includes a face extending at a smaller inclination angle (θ) than the first wall faces with respect to the placement face. a glass plate having an upper face, a lower face, and a peripheral side surface; a frame (20, 20A) having an opening smaller than the glass plate; and a low melting glass having a lower melting point than the glass plate, the glass plate being sealed to the frame (20, 20A) with the low melting glass to close the opening, wherein the frame (20, 20A) has an encircling step (30, 30A) formed on a side thereof to which the glass plate is sealed, wherein the encircling step (30, 30A) includes: a placement face situated at a recessed position relative to an upper surface of the frame (20, 20A), the placement face being in contact with a perimeter of the lower face of the glass plate to have the glass plate placed thereon; and a wall face (32, 32A) connecting the upper surface of the frame (20, 20A) and the placement face, wherein the wall face (32, 32A) includes a plurality of inner sides forming the perimeter of the opening, wherein the wall face (32, 32A) includes first wall faces situated at opposite ends of each inner side of the encircling step (30, 30A) and a second wall face (32b, 32c) situated between the first wall faces, and wherein gaps between the first wall faces and the peripheral side surface of the glass plate and a gap between the second wall face (32b, 32c) and the peripheral side surface of the glass plate are filled with the low melting glass the cover (1, 1A) being characterized in that: the frame (20, 20A) is made of metal; and that the second wall face (32b, 32c) includes a face extending at a smaller inclination angle (θ) than the first wall faces with respect to the placement face. a placement face situated at a recessed position relative to an upper surface of the frame (20, 20A), the placement face being in contact with a perimeter of the lower face of the glass plate to have the glass plate placed thereon; and a wall face (32, 32A) connecting the upper surface of the frame (20, 20A) and the placement face, wherein the wall face (32, 32A) includes a plurality of inner sides forming the perimeter of the opening, wherein the wall face (32, 32A) includes first wall faces situated at opposite ends of each inner side of the encircling step (30, 30A) and a second wall face (32b, 32c) situated between the first wall faces, and wherein gaps between the first wall faces and the peripheral side surface of the glass plate and a gap between the second wall face (32b, 32c) and the peripheral side surface of the glass plate are filled with the low melting glass the cover (1, 1A) being characterized in that: the frame (20, 20A) is made of metal; and that the second wall face (32b, 32c) includes a face extending at a smaller inclination angle (θ) than the first wall faces with respect to the placement face. the frame (20, 20A) is made of metal; and that the second wall face (32b, 32c) includes a face extending at a smaller inclination angle (θ) than the first wall faces with respect to the placement face.