A plant cultivation light source is turned on, or turned off depending on a light period and a dark period of a plant. When a portion of the light period is referred to as a first period and the other portion of the light period is referred to as a second period, the first period and the second period are alternately provided with each other, and lights having different wavelengths from each other are provided to the plant in the first and second periods, thereby increasing a content of an active ingredient in the plant.
