A lighting device may be provided that includes: a heat sink; a member which has a polygonal pillar shape having at least three sides and is disposed on the heat sink, wherein the sides are inclined at a predetermined angle toward the center of the heat sink; and a light source which is disposed on at least one among the sides of the member, wherein the light source includes: a substrate; at least two light emitting devices which are symmetrically disposed on the substrate with respect to the center of the substrate; and at least two lens units which are disposed on the light emitting devices respectively, and consequently, it is possible to meet U.S. Energy Star and ANSI specifications, to remarkably improve rear light distribution characteristics and to remove a dark portion.