PROBLEM TO BE SOLVED: To provide an interlocking mechanism which enables cancelling of accelerator lever position retention and forward/backward switching by one operation means of a forward/backward switching lever and achieves a reduction in an operation load.SOLUTION: In a forward/backward switching operation device 20 for a farm working machine which is equipped with a forward/backward switching lever 14 for operating to switch between forward travelling and backward travelling by linking to a forward/backward switching device 28 on an operation handle 8, an accelerator lever 15 for adjusting a rotational speed of an engine 3 is provided in the vicinity of an installed position of the forward/backward switching lever 14. An interlocking mechanism 30 which moves the accelerator lever 15 to a low speed side by working in association with a backward operation of the forward/backward switching lever 14 is provided between the forward/backward switching lever 14 and the accelerator lever 15. In the interlocking mechanism 30, an interlocking region α where the operation of the forward/backward switching lever 14 works in association with the accelerator lever 15 and a non-interlocking region β where the operation of the forward/backward switching lever 14 actuates the forward/backward switching device 28 and does not work in association with the accelerator lever 15 are provided.SELECTED DRAWING: Figure 6COPYRIGHT: (C)2018,JPO&INPIT【課題】前後進切換レバーの一つの操作手段で、アクセルレバー位置保持解除と前後進切換を可能とするとともに、操作荷重の減少が図れる連動機構を提供しようとする。【解決手段】操作ハンドル8に、前後進切換装置28に連係されて前後進を切換え操作する前後進切換レバー14を設けた農作業機の前後進切換操作装置20において、前後進切換レバー14の設置位置近傍にエンジン3の回転速度を調節するアクセルレバー15を設け、前後進切換レバー14とアクセルレバー15との間に、前後進切換レバー14の後進操作に連動してアクセルレバー15を低速側に移動させる連動機構30を設け、該連動機構30には、前後進切換レバー14の操作がアクセルレバー15に連動する連動範囲αと、前後進切換レバー14の操作が前後進切換装置28を作動させるがアクセルレバー15には連動しない非連動範囲βとを設ける。【選択図】図6