An advancing/retracting mechanism includes a first arm, a second arm, a first coupling part that couples the first arm and the second arm, and a second coupling part that couples a supporting body and the first arm. A transfer device is configured to move the supporting body back and forth with the first coupling part located on a first side relative to the second coupling part, by rotating the first arm and the second arm. In a first region, which is a region in the depth direction and includes an end on the front side of the rack body, a distance from the width directional center to the first supporting portion is longer than a distance from the width directional center to the second supporting portion.