PROBLEM TO BE SOLVED: To provide a light source device having a changeable range of irradiation with excitation light in an observed part and obtaining fluorescent images according to the regions of interest of various sizes.SOLUTION: The light source device includes a parallel light source portion 70 for emitting parallel light entering a light incident end surface 60 of a predetermined light guide member LG, and an irradiation range changing portion (e.g., dichroic mirror 56 and moving mechanism 57 thereof) for changing the range of irradiation with parallel light emitted from a light-emitting end surface of a light guide member 30g by changing the incident angle of an optical axis of the parallel light emitted from the parallel light source portion 70 relative to the optical axis of the light guide member LG.COPYRIGHT: (C)2013,JPO&INPIT【課題】被観察部における励起光の照射範囲を変更可能とし、種々の大きさ関心領域に応じた蛍光画像を取得可能とする。【解決手段】所定の導光部材LGの光入射端面60に入射される平行光を射出する平行光源部70と、平行光源部70から射出された平行光の光軸の導光部材LGの光軸に対する入射角度を変更することによって導光部材30gの光出射端面から射出される平行光の照射範囲を変更する照射範囲変更部(たとえばダイクロイックミラー56およびその移動機構57)とを備える。【選択図】図4
