A switching filter (17) is provided in a light source device (3) according to the present invention. The switching filter (17) has a first dichroic filter (53A) which transmits illumination light in a first wavelength band from a lamp (12) and a fluorescence observation filter (61) which transmits at least illumination light in a second wavelength band and is rotatably provided such that the first dichroic filter (53A) and the fluorescence observation filter (61) pass through an illumination light optical axis. An LED portion (51) has a blue LED (51A) which emits illumination light in the first wavelength band toward the switching filter (17). A second dichroic filter (53B) capable of transmitting illumination light from the lamp (12) and reflecting illumination light from the LED portion (51) to a condenser lens (15) is also arranged at the switching filter (17).
