An illumination apparatus which comprises a housing and a circuit board having illuminants, which can be mounted in the housing. In order to provide an illumination apparatus whose housing protects the functional components against hard environmental conditions and mechanical loads to be expected and which has a particularly compact design, the housing substantially comprises a base of annular shape, an intermediate part having a hat-like shape which accommodates the circuit board and has a guiding opening for the connection cables, and a lid part which allows a selective outlet of light.