A measuring device (40) for measuring an illumination property of an illumination system (12), which is configured for two-dimensional irradiation of a substrate (24) arranged in an illumination plane (21) with illumination radiation (20). Two differing measurement beam paths (52, 54) are formed in the measuring device, each arranged to guide the illumination radiation emitted by the illumination system onto a spatially resolving intensity detector (42) of the measuring device. A first (52) of the measurement beam paths is arranged to measure an intensity distribution in the illumination plane and the second (54) of the measurement beam paths is arranged to measure an intensity distribution in a pupil of the illumination system. The measuring device also includes an imaging optical unit (44) arranged in the first measurement beam path (52) such that the illumination radiation guided in the first measurement beam path passes through the imaging optical unit.