A plant cultivation device includes cultivation plate (110) for holding plant (140), lamp (112) that is located above the cultivation plate, and that emits light downward, transparent hollow tube (104) that is located between the lamp and the cultivation plate, and that internally has hollow section (1000), light source (100) that introduces artificial light to the transparent hollow tube, and air duct (107) that supplies air to the hollow section. The transparent hollow tube has ventilation opening (106) through which the air supplied to the hollow section is blown upward. The transparent hollow tube has prism (105) by which the artificial light travelling in a longitudinal direction of the transparent hollow tube is reflected upward, at a position of the ventilation opening in a plan view.