PURPOSE: To continue a correct steering control in the running direction of an agricultural vehicle, such as a combine harvester, in accordance with hard and soft condition of the ground, by detecting both over- and short-correction in the vehicle running direction by means of an acceleration sensor and adjusting it.

CONSTITUTION: When the direction sensor 13a on one side touches the plant stems 4 in the field and is switched on, the detected signal is transferred to the microcomputer 12 as the running direction deviation signal. Then the microcomputer 12 issues a pulse signal P, and makes the position of solenoid control valve 26a of the other side steering control block 19a to be switched into the operational position to actuate hydraulic oil cylinder 27a, forces steering clutch 22a to operate and other side crawler 2a to stop, thus having the body swung with the driving force of the crawler 2b on one side and the deviation of the running corrected. When the directional sensor 13a is switched off after this correction, the output signal P is lost and the solenoid control valve 26a is returned to the inoperative position, hydraulic oil cylinder 27a returns to inoperative position, while the stopping of the other side crawler 2a is relased and the vehicle is allowed to travel in the corrected direction.