COUPLING ANGLE DETECTION DEVICE FOR COMBINATION VEHICLE, COMBINATION VEHICLE, AND COUPLING ANGLE DETECTION METHOD FOR COMBINATION VEHICLE

A coupling angle detection device acquires a shape information of a target member having a prescribed shape and installed in a first vehicle by a shape information acquisition unit installed in a second vehicle and detects an angle formed by a direction specified based on a prescribed condition from the acquired shape information of the target member and a front-rear direction of a vehicle body of the second vehicle that is held, as a coupling angle between the first vehicle and the second vehicle. The target member is installed in the first vehicle such that the specified direction fits a front-rear direction of a vehicle body of the first vehicle.