The illumination device includes a first light emitting unit that emits light in a first wavelength band that is in an excitation light band that causes fluorescence emission using the excitation / fluorescence characteristics of the fluorescent contrast agent and is near the maximum wavelength of excitation efficiency. , A second light emitting unit that emits light in the second wavelength band not including the first wavelength band, a first light emission control unit that controls the first light emitting unit, and a second light emission control that controls the second light emitting unit. And a control unit that controls the first light emission control unit and the second light emission control unit to alternately emit light from the first light emission unit and the second light emission unit, and the control unit emits light from the second light emission unit. During operation, the first light emitting unit is not operated to emit light.照明装置は、蛍光造影剤の励起・蛍光特性を利用して蛍光発光を起こさせる励起光帯域にあって、励起効率最大波長近傍である第１の波長帯域の光を発光させる第１発光部と、第１の波長帯域を含まない第２の波長帯域の光を発光させる第２発光部と、第１発光部を制御する第１発光制御部と、第２発光部を制御する第２発光制御部と、第１発光制御部および第２発光制御部を制御することで、第１発光部および第２発光部から交互に発光させる制御部とを備え、制御部は、第２発光部の発光動作時は、第１発光部を発光動作させない。
