Abstract: An illumination system comprises a 1st signal generator to generate signals with a frequency range of the alpha rhythms of human brain waves, a 2nd signal generator to generate signals with a power spectrum distribution expressed by 1/f.sup.n, where n is between 0 and 2, and also with a frequency range below 50 Hz, a driver amplifier a and a driver amplifier b, both serving as light controllers to control the illumination of light sources according to the signals from the 1st and 2nd signal generators respectively and finally a light source 1 and a light source 2 to shed lights, and contributes to inducing a person under the light shedding from it to generate alpha rhythms without having an uncomfortable impression due to flickering illumination in a readily available illumination environment.