An imaging apparatus is provided that allows adequate observation of a fluorescence image without overlooking emitted fluorescence. An endoscope system 1 includes special-light light source 42 configured to irradiate a subject with excitation light for exciting a fluorescent substance introduced into the subject a white-light light source 41 having configured to irradiate the subject with normal light including a visible wavelength range different from the excitation light an imaging element 244 having an imaging surface for capturing an optical image of the subject irradiated with the excitation light or normal light to generate an image signal a brightness detection unit 303 configured to generate a brightness signal indicating brightness, based on the image signal generated by the imaging element 244 under irradiation with the normal light and an amplification unit 309a configured to set an amplification factor of the image signal to be generated by the imaging element 244 under irradiation with the excitation light, based on an amplification factor according to the brightness signal generated by the brightness detection unit 303.
