Provided is a plant cultivation device that improves cultivation efficiency and usability. A plant cultivation device (100) comprises: a rack unit (120) provided with cultivation racks (S) on which cultivation units (110) accommodating plants are stored as culture medium units (111) and a conveying device which moves along a horizontal movement path defined by a guide rail (149), and performs transport of the culture medium units (111) and loading/unloading of the culture medium units (111) to/from the cultivation racks (S). Multiple cultivation racks (S) constitute a cultivation rack row (C), in which the cultivation racks are arranged at multiple levels in an up-down direction. The rack unit (120) comprises: a cultivation storage (121) constituted of multiple cultivation rack rows (C) and a loading/unloading station (122) having a stock rack row (170), in which the holding frames (115) of cultivation units (110) not accommodating plants are stored as empty units. The transport device (130) performs loading/unloading of the holding frames (115) to/from the stock rack row (170).