Without it overlooks the emitted fluorescence, and to provide an imaging apparatus capable of appropriately performing observation of the fluorescent image. The endoscope system 1 includes a special light source 42 for emitting towards the said subject with excitation light for exciting a fluorescent substance introduced into the subject, a normal light including visible band different from that of the excitation light to the subject a white light source 41 to be emitted toward an imaging device 244 having an imaging surface for generating an image signal of an optical image by capturing the optical image of the subject illuminated by the excitation light or normal light, under illumination of the normal light based on the image signals by the imaging device 244 is generated, the brightness detection section 303 generates a luminance signal indicating the brightness under illumination of the excitation light at an amplification factor corresponding to the luminance signal to the brightness detecting unit 303 has generated I comprises an amplifier unit 309a for setting the gain of the image signal to the image pickup device 244 is produced.発光した蛍光を見落とすことなく、蛍光画像の観察を適切に行うことができる撮像装置を提供する。内視鏡システム1は、被写体に導入された蛍光物質を励起するための励起光を該被検体に向けて出射する特殊光光源42と、励起光と異なる可視帯域を含む通常光を被検体に向けて出射する白色光光源41と、励起光または通常光で照明された被写体の光学像を撮像して光学像の画像信号を生成する撮像面を有する撮像素子244と、通常光の照明下で撮像素子244が生成した画像信号に基づいて、明るさを示す輝度信号を生成する明るさ検出部303と、明るさ検出部303が生成した輝度信号に応じた増幅率で励起光の照明下で撮像素子244が生成する画像信号の増幅率を設定する増幅部309aと、を備える。
