A mobile agricultural machine which comprises travelling speed change members (23, 24) for effecting speed change and transmission of a drive force of an engine (21) to right and left travelling sections (2, 2), with a travelling speed change operation of a speed change operation member (68), and steering members (26, 27) for producing a difference between driving speeds of the right and left traveling sections (2, 2), with a steering operation of a steering operation member (19). The agricultural machine is constructed to shift to spin turn action while slowing down a travelling speed in accordance with an amount of operation of the steering operation member (19), and it is possible only in a series of continuous steering operations to smoothly perform actions of direct advance and course correction during farm working and spin turning actions for change of direction toward a position of subsequent working process in a field butt. IMAGE
展开▼
