According to one embodiment, there is provided a light-emitting device (110, 111, 121, 121a, 121b, 121c, 121d, 131, 141) including a light-emitting section (40, 40a, 40b, 40c, 40d), a thermal radiation member (51), and a heat conduction layer (52). The light-emitting section (40, 40a, 40b, 40c, 40d) includes a mounting substrate section (15) and a light-emitting element section (35). The mounting substrate section (15) includes a substrate (10), a first metal layer (11), and a second metal layer (12). The substrate (10) includes a first principal plane (10a) including a mounting region (16) and a second principal plane (10b) on the opposite side of the first principal plane (10a) and is insulative. The first metal layer (11) is provided on the first principal plane (10a). The first metal layer (11) includes a plurality of mounting patterns (11p, 11pa, 11pb) provided in the mounting region (16). The second metal layer (12) is provided on the second principal plane (10b) and electrically insulated from the first metal layer (11). The light-emitting element section (35) includes a plurality of semiconductor light-emitting elements (20, 20a, 20b, 20c, 20d) and a wavelength conversion layer (31). The semiconductor light-emitting elements (20, 20a, 20b, 20c, 20d) are connected to the mounting patterns (11p, 11pa, 11pb). The luminous exitance of the light-emitting element section (35) is equal to or higher than 101 m/mm 2 and equal to or lower than 1001 m/mm 2 . The thermal radiation member (51) is opposed to the second principal plane (10b). The thermal radiation member (51) has an area equal to or larger than five times the area of the mounting region (16). The heat conduction layer (52) is provided between the thermal radiation member (51) and the second metal layer (12).