PROBLEM TO BE SOLVED: To provide a riding seedling transplanter having a really compact size and having a line marker retractable within the lateral width of a seedling planting device in the housed posture of the line marker even in the case of attaching the seedling planting device as close as possible to the rear part of a traveling body for reducing the size of the riding seedling transplanter.SOLUTION: The line marker 21 is composed of a rotary marker 27 having a plurality of claws 28 on the outer circumference of a rotor and rotatably supported by a supporting arm 26 attached to a swinging arm 23 connected its base with the machine body in a vertically tiltable manner. The supporting arm 26 is attached to the swinging arm 23 in a tiltable or fixable state to direct the rotary marker 27 in the direction crossing the seedling tray 14 in the retracted state of the line marker 21.COPYRIGHT: (C)2007,JPO&INPIT【課題】乗用型苗植機のコンパクト化を図るために、苗植付装置を走行機体の後部に極力近接させた状態で装着した場合でも、線引きマーカを格納姿勢にすれば苗植付装置の横幅内に収められて、真にコンパクト化が図られた乗用型苗植機を提供することを目的とする。【解決手段】線引きマーカ21は機体に基部を軸支して上下揺動自在に設けた揺動アーム23に、回転体の外周部に複数の爪部28を設けた回転式マーカ27を回転自在に軸支した支持アーム26を装着した構成とし、線引きマーカ21の格納状態で回転式マーカ27が苗載台14と交差する方向に向くように、揺動アーム23に支持アーム26を回動及び固定自在に装着してある乗用型苗植機。【選択図】図1