Provided is a transplanting device for performing transplanting between a plurality of culture medium boards cultivating a plurality of plants planted in an aligned manner. The transplanting device includes a transplanting mechanism for transplanting the plants, where the transplanting mechanism performs alternately a step of arranging plants having been arranged in a grid form on a culture medium board of a transplanting source, into a zigzag form on a culture medium board of a transplanting destination, and a step of arranging plants having been arranged in a zigzag form on a culture medium board of a transplanting source, into a grid form on a culture medium board of a transplanting destination.