A field facet mirror for an illumination optics of a projection exposure apparatus for EUV microlithography transmits a structure of an object arranged in an object field into an image field. The field facet mirror has a plurality of field facets with reflection surfaces. The arrangement of the field facets next to one another spans a base plane. Projections of the reflection surfaces of at least two of the field facets onto the base plane differ with respect to at least one of the following parameters: size, shape, orientation. A field facet mirror results which can ensure a uniform object field illumination with a simultaneously high EUV throughput.
