A plant cultivation device includes a light source unit having a first light source emitting stimulation light in a UV region toward a plant and a second light source emitting background light toward the plant, the background light having a different peak wavelength than the stimulation light. The second light source emits the background light during a light period and stops emission of the background light during a dark period. In addition, the first light source emits the stimulation light for a certain period of time during the light period. Further, a cumulative amount of the stimulation light emitted from the first light source is 0.036 J or more per day.
