A light source and an illumination device including the light source are provided. By adjusting peak wavelengths, peak intensities and color coordinates of blue light, red light and green light in the illumination light emitted by the light source to preset ranges, the illumination light emitted by the light source has a specific spectral distribution. In another embodiment, a specific light color is achieved by a specific phosphor ratio. Not only the color theory is considered for the evaluation of the lighting effect, but also the influence of the spectrum on the actual lighting effect is considered. At the same time, the influence of the luminescent material on the spectrum is considered. Thus, a light source having a high comfort, a high preference, a high color rendering index, and a high color gamut index is obtained, and the light source has a similar effect to the sunlight.