[Problem] To provide a plant cultivation device, by which a plant can be efficiently cultivated using the circadian rhythms of the plant inherent thereto, and a method therefor.[Solution] A plant cultivation device comprising: a housing (11) having a cultivation space (13) in which a plant is to be enclosed a light source (12) which is provided in the upper part of the housing (11) for emitting cultivation light required for the growth of the plant, said plant being enclosed in the cultivation space (13) a light source controller (21) for switching the light source (12) a computer (20) for controlling the light source controller (21) a keyboard (30) which is an input means for setting light-dark cycles a memory unit (22) which is a storage means for storing the light-dark cycles having been set by using the keyboard (30) and a display (40) which is an indication means for indicating temperature and humidity in the cultivation space (13). In the aforesaid device, for example, the light period is set to 11 hours and the dark period is set to 11 hours. Then, the switching of the light source (12) is controlled so that the dark period is terminated 1 to 3 hours before the dawn in the circadian rhythms of the plant.Linvention concerne un dispositif de culture de plante, grâce auquel une plante peut être efficacement cultivée en utilisant les rythmes circadiens de la plante qui lui sont inhérents, et un procédé associé. Linvention concerne un dispositif de culture de plante comprenant : une enceinte (11) comprenant un espace de culture (13) dans lequel une plante doit être contenue une source lumineuse (12) qui est placée dans la partie supérieure de lenceinte (11) pour émettre de la lumière de culture nécessaire à la croissance de la plante, ladite plante étant contenue dans lespace de culture (13) une commande de source lumineuse (21) pour commuter la source lumineuse (12) un ordinateur (20) pour commander la commande de source lumineuse (21) un clavier (30) qui est
