There is provided a facet mirror device comprising a facet element and a support unit, the support unit supporting the facet element. The support unit comprises a first support element and a second support element, the second support element being connected to the facet element to support the facet element. The first support element is connected to the second support element to support the second support element, the first support element being connected to the second support element via at least one flexure unit, the flexure unit comprising at least one flexure.