TRAVEL ASSISTANCE DEVICE

A travel assistance device configured to execute travel assistance when a plurality of vehicles form a vehicle group and travel in a line. The travel assistance device includes: a first control unit configured to, if there is lane-change instruction for the vehicle group, cause an end-of-line vehicle to change lanes, such vehicle being the vehicle from among the plurality of vehicles forming the vehicle group that is positioned at the end of the line; and a second control unit configured to, following the lane change of the end-of-line vehicle, allow a lane change for at least one vehicle that is other than the end-of-line vehicle and that is one of the vehicles forming the vehicle group.