PROBLEM TO BE SOLVED: To dissolve the troublesomeness of an operator by setting and storing an adjusted position automatically, although the operator adjusts an a mowing height to a reference height to store an adjustment value in the construction of the prior art so that the prior art has a troublesome adjustment and takes a long time.SOLUTION: In a combine-harvester equipped with a bowing height grounding sensor (25) for detecting a ground height in contact with the ground at the bottom of a liftable cutting pretreatment part (3) thereby to control the cutting height automatically, if a cutting height control switch (29) is operated while the bottom part of said the cutting pretreatment part (3) is being in contact with the ground, said cutting pretreatment part (3) is caused to perform an output rise for a predetermined time period so that the sensor value at the output ending time is automatically stored as a reference value at a descent time.SELECTED DRAWING: Figure 4COPYRIGHT: (C)2017,JPO&INPIT【課題】従来構成のものでは、オペレータが基準高に刈高さを合わせて調整値を記憶するものであり、調整が煩わしく、時間がかかる問題があった。 本発明は、自動的に調整位置を設定し、記憶することで作業者の煩雑さを解消することにある。【解決手段】本発明は、昇降可能な刈取前処理部(3)の底部に地面と接触して対地高さを検出する刈高さ接地センサ(25)を設けて刈高さを自動制御するコンバインにおいて、前記刈取前処理部(3)の底部を地面に接触させた状態で刈高制御スイッチ(29)を操作すると、前記刈取前処理部(3)を所定時間上昇出力を行い、出力終了時点のセンサ値を下降時基準値として自動的に記憶させる。【選択図】図4