An X-ray imaging apparatus according to an embodiment of the present disclosure includes an X-ray tube, a photon counting X-ray detector, and a filter unit. A generating unit of the X-ray tube is configured to generate X-rays. The photon counting X-ray detector is configured to count photons contained in the X-rays. The filter unit is provided between the X-ray tube and the photon counting X-ray detector. The filter unit includes a first filter and a second filter. The first filter is configured to shape a spectrum of the X-rays. The second filter is configured to generate X-ray fluorescence on the basis of X-rays related to a spectrum resulting from the shaping by the first filter.