This invention relates to a function switch on handle of motorcycle, in which a light transmissive zone is formed on the housing thereof. A light emitting source is provided at the interior of the function switch which is coupled to the switches for small light and large light. In this manner, when driver turns on small light or large light, the light emitting source can also be energized to radiate light and the light beam emitted from the light emitting source can be projected out through the light transmissive zone of the housing so as to highlight the pattern of the light transmissive zone.