Provided are a light scanning apparatus and an image forming apparatus including the same. The light scanning apparatus includes a housing, which includes a space therein; a light source module, which is installed at the housing and emits a light beam; a light deflector, which is installed on the bottom surface of the housing and deflects the light beam emitted by the light source module; an image forming optical system, which is installed in the space inside the housing and forms an image of the light beam deflected by the light deflector on a surface to be scanned; a flow restricting unit, which is arranged in the space inside the housing and restricts air flows formed as the light deflector is driven; and a cover, which covers the housing.