Fuente: WIPO "tomato" Provided is a plant cultivation method that performs light control of distribution of glucose produced by photosynthesis to a primary metabolic pathway and a secondary metabolic pathway, and that can control metabolite production in each metabolic reaction. In at least a part of a cultivation period from sowing to harvest, irradiation is performed with main light for photosynthesis and additional light for promoting photosynthesis of a plant via the main light. The additional light includes additional signal light the light intensity of which varies periodically and additional relaxation light the light intensity of which changes more gently than the additional light. The wavelength of the additional signal light includes a light absorption wavelength band of a red light receptor in the plant.