To make it possible for an incompetent worker to easily move up and down the movable table by himself / herself.SOLUTION: A cultivation rack is arranged in a space surrounded by a support pillar, and a movable base 3 which can be raised and lowered with a lighting device is located above the cultivation rack. The positioning mechanism for positioning the movable base 3 at a plurality of height positions includes a shaft body 6 provided at both end positions of opposite sides of the movable base 3, a support plate 7 provided at a position opposed to the shaft body 6 of each support column . Each support plate 7 is formed with a guide groove 70 for slidably engaging the shaft body 6. Each of the guide grooves 70 has a plurality of stages of lateral grooves 71 and a longitudinal groove portion 72 communicating between the lateral grooves 71, 71, and a pivotal support portion 75 for positioning the shaft body 6 in each of the lateral grooves 71 is provided. Each support plate 7 located on one side a of the opposite side of the movable base 3 and each support plate 7 positioned on the side of the other side b are arranged in such a manner that the longitudinal and lateral grooves are arranged in line symmetry A guide groove 70 is formed.(FIG.【課題】非力な作業者でも、可動台の昇降作業をひとりで容易に行えるようにする。【解決手段】支柱で囲まれる空間内に栽培棚が配置され、その上方に照明装置が設けられた昇降可能な可動台3が位置する。可動台3を複数の高さ位置に位置決めする位置決め機構は、可動台3の対辺の両端部位置にそれぞれ設けられる軸体6と、各支柱の軸体6と対向する位置に設けられる支持板7とを含む。各支持板7には軸体6がスライド自由に係合する案内溝70が形成されている。各案内溝70は、複数段の横溝部71と横溝部71,71間を連通させる縦溝部72とを有し、各横溝部71に軸体6を定位させる軸支部75が設けられている。可動台3の対辺の一方の辺aの側に位置する各支持板7と他方の辺bの側に位置する各支持板7とは、縦横の各溝部が線対称の配置となるようにそれぞれの案内溝70が形成されている。【選択図】図8
