PURPOSE: To maintain a proper steering position when turn operation from the end part of a working process to the start end of a next working process ends by starting steering control along with the detection of a border when the working vehicle turns by larger than a specific angle.

CONSTITUTION: An image pickup means S1 picks up an image of a place by and before the vehicle body in two dimensions. A border detecting means 101 detects the border between an unprocessed work place and a processed work place in the vehicle lateral direction according to the image pickup information. A steering control means 102 performs steering control for an automatic travel in respective plural working processes. A turn control means 103 controls movement to the start end part of a next working process at the tail end part of one working process according to a turn pattern which is previously set and stored. A steering control means 102 starts control operation once the border detecting means 101 detects the border after the turn control means 103 perform turning operation by more than the specific angle. Consequently, the setting of a preliminary travel section, etc., at a place before the next working process can be omitted.