Provided is a prime mover structure for a combine that can easily perform maintenance and inspection work of a hydraulic continuously variable transmission. A combiner driving portion structure in which a fan (31) is provided between an engine (E) and a radiator (30), wherein the fan (31) is driven in a forward direction and a reverse direction. A transmission (10) is provided, and an electrical component room (26) is provided on the upper side of the engine room (6). The bottom wall (28) of the electrical component chamber (26) is recessed upward, The upper part of the hydraulic continuously variable transmission (10) was disposed on the lower surface side of the recessed portion. [Selection] Figure 3【課題】油圧式無段変速装置の保守・点検作業を容易に行うことができるコンバインの原動部構造を提供する。【解決手段】エンジン（Ｅ）とラジエータ（３０）の間にファン（３１）を設けたコンバインの原動部構造であって、ファン（３１）を正転方向および逆転方向に駆動する油圧式無段変速装置（１０）を設け、エンジンルーム（６）の上側には電装部品を内装する電装室（２６）を設け、電装室（２６）の底壁（２８）を上側に向けて窪ませ、この窪ませた部分の下面側に油圧式無段変速装置（１０）の上部を配置した。【選択図】図３
