A motor vehicle headlight and a motor vehicle illumination device, which includes at least one light source for emitting light rays, a wavelength conversion element arranged to receive the light rays on a zone and to re-emit a light radiation to produce a light beam, a reflecting element for redirecting light rays from the light sources towards the conversion element, and a scanning apparatus configured to scan the reflecting element with the light rays in a first direction between extreme positions, the reflecting element being configured to reflect light rays at said extreme positions to a central part of the zone so as to form the central part of the light beam.