The present invention is designed to overcome the disadvantages of X-ray imaging having difficulty in high-sensitivity measurement and of optical imaging having difficulty in high-spatial-resolution measurement, when used for diagnostic purposes. The present invention provides an imaging apparatus including an X-ray tube, a detector having sensitivity to X-rays and light, and a processing unit that processes the result of detection. In the imaging apparatus, the processing unit processes, as a first signal, a signal detected by the detector during an irradiation period in which an X-ray source provides X-ray irradiation, and processes, as a second signal, a light signal detected by the detector during a period other than the irradiation period.