An illumination device includes an irradiation unit having a light emitting element and fluorescent bodies excited by the light from the light emitting element to radiate light of different wavelengths. The irradiation unit irradiates composite light of blue, green and red lights having half value widths of 20-40 nm, 110-150 nm and 80-110 nm and peak wavelengths of 440-465 nm, 545-555 nm and 630-650 nm, respectively. If the output value of the light in a wavelength 435-465 nm is assumed to be 100%, the output values of the lights having wavelengths of 490, 530 and 639 nm fall within 46-56%, 59-77% and 75-93%, respectively. The ratio of the output value of the light of 630 nm to that of the light of 530 nm falls within 73-86%.