A transplanting device and a transplanting method are provided in which a large number of times of transplanting are allowed to be achieved at one time of work in a simple method. A transplanting device performing transplanting between a plurality of culture medium boards 200 cultivating a plurality of plants planted in an aligned manner, including a transplanting mechanism 1 transplanting the plants, wherein the transplanting mechanism 1 performs alternately a step of arranging plants having been arranged in a grid form on a culture medium board 200 of transplanting source, into a zigzag form on a culture medium board 200 of transplanting destination and a step of arranging plants having been arranged in a zigzag form on a culture medium board 200 of transplanting source, into a grid form on a culture medium board 200 of transplanting destination.