PROBLEM TO BE SOLVED: To make it possible to reliably perform PTO transmission.SOLUTION: A PTO transmission device comprises: two kinds of PTO shafts 40; a PTO drive part 20; a storage part 46; a PTO transmission operation unit 47; a PTO shaft detection sensor 80; and a PTO transmission sensor 90. Two kinds of PTO shafts 40 are detachably mounted onto an airframe, and are connected to a driven part which is connected to the airframe. The PTO drive part 20 has a shift mechanism, and rotates the PTO shaft 40, which is mounted onto the airframe, at a rotation number shifted by a shift mechanism 39. The storage part 46 stores the PTO shaft 40 which is not mounted onto the airframe. The PTO transmission operation unit 47 performs shift operation for the shift mechanism 39. The PTO shaft detection sensor 80 detects a kind of the PTO shaft 40 which is stored in the storage part 46. The PTO transmission sensor 90 detects an operation state of the PTO shift operation unit 47.SELECTED DRAWING: Figure 11【課題】PTO変速を確実に行うこと。【解決手段】PTO変速装置は、2種類のPTO軸40と、PTO駆動部20と、収納部46と、PTO変速操作部47と、PTO軸検出センサ80と、PTO変速センサ90とを備える。2種類のPTO軸40は、機体に着脱自在に装着され、機体に連結された被駆動部に接続する。PTO駆動部20は、変速機構を有し、機体に装着されるPTO軸40を変速機構39によって変速された回転数で回転させる。収納部46は、機体に装着されないPTO軸40を収納する。PTO変速操作部47は、変速機構39に対する変速操作を行う。PTO軸検出センサ80は、収納部46に収納されたPTO軸40の種類を検出する。PTO変速センサ90は、PTO変速操作部47の動作状態を検出する。【選択図】図11