Provided is a plant cultivation device (1) where installation work, repair, partial improvement or remodeling work can be performed easily. A plurality of seedling growing units (2) are connected to each other in series. The seedling growing unit (2) has a case (5) which has both ends thereof opened and can cover a peripheral surface of the seedling growing unit (2). A tray mounting base (12), a conveyance device (15), an illumination unit (16), and a water supply/discharge facility (17) are disposed inside the case (5). The cases of the seedling growing units (2) are connected to each other thus forming a continuous cylindrical space (60). A series of conveyance units are formed by the conveyance devices inside the cases. Cultivation trays are disposed in the continuous cylindrical space formed by the cases, and the cultivation trays are movable toward a downstream side by the conveyance unit in a state where the cultivation tray strides over the case.
