An imaging apparatus includes: an excitation light emission unit that irradiates a subject with excitation light for exciting a fluorescent substance introduced into the subject; a normal light emission unit that irradiates the subject with normal light including a visible wavelength range different from the excitation light; an imaging unit that forms an optical image of the subject irradiated with the excitation light or normal light on an imaging surface to generate an image signal; a brightness signal generation unit that generates a brightness signal indicating brightness, based on the image signal generated by the imaging unit under irradiation with the normal light; and an amplification unit that sets an amplification factor of the image signal to be generated by the imaging unit under irradiation with the excitation light, based on an amplification factor of the image signal according to the brightness signal generated by the brightness signal generation unit.