PROBLEM TO BE SOLVED: To provide a steering controller of a working vehicle, which can automatically steer a machine frame along crops of a field without separating from a predetermined traveling direction without depending on the responding performance of a transmission and even when a machine frame position-detecting means is placed in a detection-impossible area.SOLUTION: This steering controller of the working vehicle includes a steering control means 23a for controlling steering operation means 22a, 22b so that a correction power is outputted on the basis of a detection value of the machine frame position-detecting means 16 to make the machine frame to travel along the crops M of the field, and an operation means 23b for calculating a difference between the detection values of right and left revolutions number detection means 26a and 26b, when the output of the correction power of the steering control means 23a is started, wherein the steering control means 23a stops the output of the correction power, when the calculation value of the operation means 23b becomes equal to or higher than a preset value.COPYRIGHT: (C)2011,JPO&INPIT【課題】トランスミッションの応答性能に拠らず、さらに、機体位置検出手段が検出不能域に存在する場合であっても、機体を、所定の進行方向から外れることなく圃場の作物に沿って自動操向させることのできる作業車の操向制御装置を提供すること。【解決手段】機体位置検出手段16の検出値に基づいて、修正出力を出して機体が圃場の作物Mに沿うように操向操作手段22a,22bを制御する操向制御手段23aと、操向制御手段23aが修正出力の出力を開始すると、右及び左の回転数検出手段26a,26bの検出値の差を演算する演算手段23bとを備え、演算手段23bの演算値が設定値以上になると、操向制御手段23aが修正出力の出力を停止するように構成する。【選択図】図3
