To provide comfort (color rendering properties) and security/safety for human life at night by reducing insect luring properties, adverse effect on plants and influence of light on the natural ecosystem for the purpose of symbiosis of human and the natural ecosystem.

Slurry prepared by mixing zinc oxide with a green inorganic dye is coated on a surface of an outside bulb of a fluorescent mercury lamp. This lamp is so structured as to decrease cultivation radiation efficiency for plants by a light quality balance with green light increased by cutting ultraviolet radiation below 380 nm by 90% and by reducing blue light. The lamp is composed by decreasing the cultivation radiation efficiency for plants in the range of 15-20% by reducing blue light in the range of 25-30% and by increasing green light in the range of 10-15%.