Embodiments of the present disclosure provide a collimating device and a ray inspection device. The collimating device comprises: a beam guiding cylinder, a first collimator mounted at an inlet end of the beam guiding cylinder; a second collimator mounted an outlet end of the beam guiding cylinder; a beam guiding cylinder adjusting device disposed adjacent to the inlet of the beam guiding cylinder to adjust a direction of the beam guiding cylinder such that the first collimator is aligned with the first direction. The outlet end of the beam guiding cylinder is fixed to the frame and the second collimator is aligned with an object to be irradiated by a radiation beam, and the beam guiding cylinder is configured to have flexibility to allow the adjusting device to adjust a direction towards which the inlet end of the beam guiding cylinder is directed, in a direction transverse to the first direction.