A calibration apparatus for calibrating a scattered-light measuring device that is embodied to measure a particle concentration in motor vehicle exhaust gases, comprises at least one scattering body that has a number of scattering centers having a defined size and a defined mutual spacing. The scattering centers are disposed in such a way that the scattering body, upon irradiation with light from a light source, delivers scattered light having an intensity and a distribution predetermined by the scattering body.