The invention provides a seedling planting device. The seedling planting device is configured in a way that a support part is provided with rollers, a seedling holding bench is driven in a reciprocating and transverse feed manner along the support part (rollers) in the horizontal direction, and the seedling planting device is properly provided with the rollers and a seedling taking-out number changing part. In the seedling planting device, a support part (24) is arranged along a plurality of planting transmission cases (8) in the horizontal direction, and the support part (24) is provided with rollers (support units 40) which support the lower part of a seedling holding bench (12). The seedling planting device is provided with a seedling taking-out number changing part (28a), the seedling taking-out number changing part (28a) changes the position of the support part (24) in the vertical direction, and the number of seedlings taken out by a planting arm (10) is changed. The seedling taking-out number changing part (28a) is arranged at one transverse side of the planting transmission cases (8) in the horizontal direction, and the rollers (support units 40) are arranged at the other transverse side of the planting transmission cases (8) in the horizontal direction.
