PROBLEM TO BE SOLVED: To prevent falling of waste straws to an exhaust muffler and keep safety of a worker operating at the rear of an engine, by arranging an exhaust muffler with an oxidation catalyst between a string storage case for storing a binding string and the engine mounted at the rear and in the rear lower space of the string storage case.SOLUTION: A binder includes a reaping bundling unit (3) in the front part of a traveling vehicle body (2) and an engine (4) at the rear of the traveling vehicle body (2). The binder is configured such that the grain culm after grass division is raised and cut from the root using the reaping bundling unit (3) driven by the engine (4), and is cross-fed to one side of left and right and is bound with a posture resting in the front side of a cross-feed guide plate (8), and is discharged outside a machine. An exhaust muffler (13) with an oxidation catalyst for purifying waste gas of the engine (4) is arranged in a space part being the rear lower part of a string storage case (10) for storing the binding string installed in the rear of the cross-feed guide plate (8) and formed in the position between the engine (4) and itself.SELECTED DRAWING: Figure 1【課題】酸化触媒を備えた排気マフラーを結束紐を収納する紐収納ケースとその後方に搭載したエンジンとの間で、かつ、紐収納ケースの後部下方空間に配置することで、排気マフラーへの藁屑等の落下を防ぎ、エンジン後方で運転する作業者の安全性を保つ。【解決手段】走行車体（２）の前部に刈取結束部（３）を、走行車体（２）の後部にエンジン（４）を備え、エンジン（４）によって駆動される刈取結束部（３）によって、分草後の穀稈を引起して株元部から切断し、横送り案内板（８）の前面側に凭せ掛けた姿勢で左右一側に横送りして結束し機外に放出する形態のバインダにおいて、横送り案内板（８）の後側に設置した結束紐を収納する紐収納ケース（１０）の後部下方であって、エンジン（４）との間の位置に形成された空間部に、エンジン（４）の排気ガスを浄化する酸化触媒を備えた排気マフラー（１３）を配置する。【選択図】図１
