The optical assembly disclosed in the embodiment includes a housing having an inclined bottom surface, a plurality of inner surfaces around an outer periphery of the bottom surface, and a receiving space in which an upper portion is opened; and a lighting module disposed on the inclined bottom surface, wherein the lighting module includes a substrate inclinedly disposed on the inclined bottom surface; at least one light emitting device disposed on the substrate; and a resin layer sealing the light emitting device and the substrate, wherein an upper surface of the resin layer emits light by diffusing light emitted from the light emitting device, wherein the plurality of inner surfaces includes a first inner surface adjacent to the light emitting device, a second inner surface facing the first inner surface, and third and fourth inner surfaces facing each other and disposed between the first and second inner surfaces, wherein a height between the bottom surface of the housing and an upper surface of the housing increases from the first inner surface toward the second inner surface, and decreases from the third inner surface toward the fourth inner surface.