A lighting device 1 includes a heat sink 2, a substrate 3 attached to a mounting portion 11 of the heat sink 2, a plurality of light sources 4 mounted on the substrate 3, and a cap 6 electrically connected to the substrate 3 while fixed to a rear portion of the heat sink 2 through a casing 5. The heat sink 2 has a three-dimensional shape including a plurality of mounting portions 11a, 11b and 11c facing in directions different from each other and provided at least at a front-end surface 12 of the heat sink 2. At least the front-end surface 12 is exposed to outside, and a plurality of heat-releasing fins 2a is provided around the front-end surface 12. The lighting device has a higher heat-releasing property, and can enlarge an illuminated area.