To provide a light source device capable of enhancing the upper limit of the emission intensity of the illumination light higher than the conventional level while retaining the color balance suitable for observing an output image.

The light source device includes an illumination light emitting part capable of emitting first illumination light and second illumination light with a different wavelength band than the first illumination light, and a light emission control part for controlling the output value of integration of the first and second illumination light. The light emission control part retains the same length of emission period of the first illumination light and second illumination light by applying either a first control function related to the emission intensity of the first illumination light or a second control function related to the emission intensity of the second illumination light according to the change of dimming signals for dimming in the light source device, and changes the output value of integration of the first illumination light and second illumination light while retaining the ratio of the output values of integration between the first illumination light and the second illumination light.