A travel assistance device for assisting traveling of a subsequent vehicle following a vehicle group in the form of vehicle platooning, the travel assistance device being located in a last vehicle of a plurality of vehicles included in the vehicle group, the travel assistance device including: an information acquiring unit for acquiring information indicating right/left turning vehicles that turn right or left at an intersection among the vehicles and information indicating deceleration timing of a first vehicle from front among the right/left turning vehicles; and a direction indicator controlling unit for turning on a direction indicator of the last vehicle at the deceleration timing of the foremost right/left turning vehicle.