PROBLEM TO BE SOLVED: To easily and quickly switch the state of a plurality of preliminary seedling placing bases by automatically changing the attitude of movable stoppers in association with switching the state of the plurality of preliminary seedling placing bases.SOLUTION: The plurality of preliminary seedling placing bases can be switched into an overlapping state in which the plurality of preliminary seedling placing bases overlap in vertical multistages in a plan view and into a deployed state in which the plurality of preliminary seedling placing bases are deployed in a substantially straight line in a longitudinal direction. The preliminary seedling placing bases are provided with the movable stoppers 270, 280 constituted to be changeable into a working attitude of impeding the movement of seedlings placed on the preliminary seedling placing bases and into a non-working attitude of permitting the movement of seedlings placed on the preliminary seedling placing bases. When the presence of seedlings is detected by a detecting means for detecting the presence/absence of seedlings placed on the preliminary seedling placing bases, the movable stoppers 270, 280 are changed into the working attitude, and when the absence of seedlings is detected by the detecting means, the movable stoppers 270, 280 are changed into the non-working attitude.COPYRIGHT: (C)2013,JPO&INPIT【課題】複数の予備苗載せ台の状態切換に伴って可動ストッパを自動的に姿勢変更することができ、複数の予備苗載せ台の状態切換を簡易迅速に行うことができるようにする。【解決手段】複数の予備苗載せ台が上下多段となって平面視で重複した重複状態と、複数の予備苗載せ台が前後向きに略一直線状になって展開した展開状態とに切換可能に構成する。予備苗載せ台に可動ストッパ270,280を備えて、可動ストッパ270,280を、予備苗載せ台に載置された苗の移動を阻止する作用姿勢と、予備苗載せ台に載置された苗の移動を許容する非作用姿勢とに姿勢変更可能に構成する。予備苗載せ台に載置される苗の存否を検出する検出手段により、苗の存在が検出されると、可動ストッパ270,280が作用姿勢に姿勢変更され、検出手段により苗の不存在が検出されると、可動ストッパ270,280が非作用姿勢に姿勢変更される。【選択図】図28
