The utility model provides a plant cultivation device. According to the plant cultivation device, the densities of photon beams emitted by all plants which are planted in cultivation tanks carried by carrying portions of a cultivation frame can be made uniform. The plant cultivation device is provided with the illuminating devices (5) which are arranged on the cultivation frame at intervals and located above the carrying portions used for carrying the cultivation tanks in a spaced mode. Each illuminating device is provided with a frame (15) of a frame shape, multiple LED lamps (16) and a plate-like reflection component (17), wherein the LED lamps are mounted on the frame in a freely detachable mode, the plate-like reflection component is mounted on the frame in a freely detachable mode and located above the LED lamps, and the reflecting surface of the plate-like reflection component faces downwards. A reflection component embedding groove (28) is formed in the part, above the LED lamps, of the frame of each i
