A work vehicle coordinating system for carrying out a ground work in a central work land and a headland extending around the central work land by an unmanned steerable sub work vehicle and a man-steered main work vehicle in cooperation with each other, the system comprises: a main vehicle position detection module for detecting a position of the main work vehicle; a sub vehicle position detection module for detecting a position of the sub work vehicle; a central work land path calculation section for calculating a central work land traveling path to be used by the sub work vehicle in an unmanned steered work traveling in the central work land, the system being characterized in that it further comprises: a first steering control section configured for unmanned-steering of the sub work vehicle ahead of the main work vehicle, based on the position of the sub work vehicle detected by the sub vehicle position detection module and on the central work land traveling path calculated by the central work land path calculation section; a headland path calculation section configured to calculate a headland traveling path to be used for unmanned steered traveling of the sub work vehicle based on a traveling path of the main work vehicle in the headland; and a second steering control section configured for unmanned-steering of the sub work vehicle to follow the main work vehicle, based on the position of the sub work vehicle detected by the sub vehicle position detection module and on the headland traveling path calculated by the headland path calculation section. a main vehicle position detection module for detecting a position of the main work vehicle; a sub vehicle position detection module for detecting a position of the sub work vehicle; a central work land path calculation section for calculating a central work land traveling path to be used by the sub work vehicle in an unmanned steered work traveling in the central work land, the system being characterized in that it further comprises: a first steering control section configured for unmanned-steering of the sub work vehicle ahead of the main work vehicle, based on the position of the sub work vehicle detected by the sub vehicle position detection module and on the central work land traveling path calculated by the central work land path calculation section; a headland path calculation section configured to calculate a headland traveling path to be used for unmanned steered traveling of the sub work vehicle based on a traveling path of the main work vehicle in the headland; and a second steering control section configured for unmanned-steering of the sub work vehicle to follow the main work vehicle, based on the position of the sub work vehicle detected by the sub vehicle position detection module and on the headland traveling path calculated by the headland path calculation section. a first steering control section configured for unmanned-steering of the sub work vehicle ahead of the main work vehicle, based on the position of the sub work vehicle detected by the sub vehicle position detection module and on the central work land traveling path calculated by the central work land path calculation section; a headland path calculation section configured to calculate a headland traveling path to be used for unmanned steered traveling of the sub work vehicle based on a traveling path of the main work vehicle in the headland; and a second steering control section configured for unmanned-steering of the sub work vehicle to follow the main work vehicle, based on the position of the sub work vehicle detected by the sub vehicle position detection module and on the headland traveling path calculated by the headland path calculation section.