PROBLEM TO BE SOLVED: To provide an illumination system that can create day and night environments and maintain proper visibility and color discriminability of equipment, etc. under even a dark condition.SOLUTION: An illumination system 1 has an illumination device 2, and a control device 3 for the illumination device 2. The illumination device 2 has a low color temperature light source 2L for emitting low color temperature light L having a correlation color temperature of 2000 to 2500K. The lower color temperature light L has a peak wavelength of radiation intensity in the wavelength range from 550 to 700 nm, the radiation intensity of the wavelength range from 440 to 500 nm is equal to 1/5 of the radiation intensity of the peak wavelength or less, and a general color rendering index Ra is equal to 60 or more. The control device 3 controls turn-on of the illumination device 2 so that the normal illuminance on an irradiation target face to which light is irradiated by the low color temperature light source 2L is equal to 1 to 100 Lx. Visibility and color discriminability can be maintained under a dark condition by the low color temperature light L whose general color rendering index Ra is equal to 60 or more in the range from 2000 to 2500K.
