To allow work vehicles to perform tasks within a designated area of the field without reducing work efficiency. [Solution] The area adjustment
system 99 comprises an adjustment unit 35 and a travel path setting unit 34. The adjustment unit 35 can adjust the central work area included in the field and the
headland area set around the central work area. The travel path setting unit 34 sets a first work path that drives the
tractor 1 to work in the central work area and a second work path that drives the
tractor 1 to work in the
headland area, based on the working width of the
tractor 1. If the expected work area that is expected to be worked on by the tractor 1 traveling along the first work path becomes smaller than the central work area in a second direction perpendicular to the first direction which is the direction of travel of the tractor 1, and an unworked area occurs in the central work area, the adjustment unit 35 adjusts the central work area and the
headland area so that the unworked area is included in the headland area.