A travel assistance device includes an actuator and an electronic control unit. The electronic control unit is configured to predict a future position of a vehicle and an object, set an assistance range around the vehicle, determine whether an avoidance start condition is satisfied and in which of a first roadway area, a second roadway area, and a sidewalk area the object is positioned, set the avoidance start condition and a movement range of the object, so that the avoidance start condition is more easily determined to be satisfied when the object is in the first roadway area than when the object is in the second roadway area, and more easily determined to be satisfied when the object is in the second roadway area than when the object is in the sidewalk area, and perform a collision avoidance operation when the avoidance start condition is satisfied.