PROBLEM TO BE SOLVED: To provide a mixed simultaneous irradiation type endoscope system obtaining an excellent special optical image.SOLUTION: A xenon lamp 30 emitting broadband light BB is provided inside a light source device 13. A bandpass filter 31 transmitting green narrowband light Gn of the broadband light BB is disposed movably forward and backward on the optical path of the broadband light BB. A blue LED 33 emitting blue narrowband light Bn is provided inside the light source device 13 such that the blue narrowband light Bn is nearly orthogonal to the optical path of green broadband light Gn. A dichroic mirror 35 is disposed movably forward and backward in a position where the optical path of the green broadband light Gn and the optical path of the blue narrowband light Bn nearly cross. The dichroic mirror 35 emits the green broadband light Gn and the blue narrowband light Bn onto an observed portion. It is not necessary to use a green LED having small emission light intensity as a light source of the green narrowband light Gn. Thus the light intensity of the green narrowband light and the blue narrowband light is sufficient secured, so that the excellent special optical image can be obtained.
