A light emitting module includes a module body, a light source unit, a plurality of heat dissipation fins, an air hole formed through the module body for allowing air to flow therethrough, an air guide unit formed at an edge of the air hole such that the air guide unit communicates with the air hole to guide air, and an optical cover covering the light source unit. The optical cover has a cover hole at a location corresponding to the air hole. The optical cover includes an inner partition wall located around a periphery of the cover hole and extending into the module body at the periphery of the air hole. The optical cover also includes an outer partition wall located at a periphery of the optical cover and defining a closed space in which the light source unit is located, the outer partition wall extending into the module body.