The object of the invention is a method and an apparatus for transmitting microbe-destroying UV light produced with one or more UV LEDs from a light source to the target of the light. In the solution according to the invention, the properties of the UV light being produced are adjusted according to the need of the target, and the UV light is transmitted from the light source to the target of the light via a flexible optical fiber element. In addition to transmitting microbe-destroying UV light, other functions enabled by optical fibers are transmitted via the same optical fiber element.