To provide a seedling transplanter which surely perform vertical feeding of a tray.SOLUTION: A seedling transplanter 1 comprises: a tray supply device 100 for supplying trays 20 on which seedlings 22 are stored; a tray transport path moving device 170 for feeding the tray supply device in a lateral direction; a take-out device 200 and seedling planting device 300 for taking out the seedlings from the tray, and planting the tray on a farm field. The tray supply device comprises: a tray feeding rod 121 for feeding the trays in a vertical direction; a vertical feeding arm 140 whose one end is rotatably attached to the tray supply device, whose the other end is coupled to the tray feeding rod; and a vertical feeding driving arm 150 whose one end is fixed to the vertical feeding rotary shaft 151, whose the other end rotates along a shape of a lower end edge of the vertical feeding arm, for vertically moving the vertical feeding arm. The vertical feeding arm 140 has a rod compulsive depression part 143d by which the vertical feeding arm is rotated compulsively downward, by force applied by the vertical feeding driving arm while rotating.SELECTED DRAWING: Figure 6【課題】トレイの縦送りが確実に行える苗移植機を提供する事。【解決手段】苗22を収容したトレイ20を供給するトレイ供給装置100と、トレイ供給装置を横方向に送るトレイ搬送路移動装置170と、トレイから苗を取り出して、圃場に植え付ける取出装置200及び苗植付装置300と、を備えた苗移植機1であって、トレイ供給装置は、トレイを縦方向に送るトレイ送りロッド121と、一端部がトレイ供給装置に回動可能に取り付けられ、他端部がトレイ送りロッドに連結された縦送りアーム140と、一端部が縦送り回動軸151に固定され、他端部が縦送りアームの下端縁部の形状に沿って回動することで、縦送りアームを上下に回動させる縦送り駆動アーム150と、を有し、縦送りアーム140は、縦送り駆動アームが回動しながら及ぼす力によって、縦送りアームが強制的に下方に回動させられるロッド強制押し下げ部143dを有している、ことを特徴とする。【選択図】図6