A driving support apparatus comprising: an image acquiring section that acquires a captured image of an area behind a vehicle supported by the apparatus, the area including a tow coupler at a rear portion of the vehicle and a tow-target coupler of a tow-target vehicle to be coupled to the tow coupler; and a superimposing section that superimposes a pair of left and right planar predicted-trajectory guide marks (405, 406) in accordance with steering operation of the vehicle supported by the apparatus, on the captured image acquired by the image acquiring section and that outputs the superimposed image, wherein each of the pair of left and right planar predicted-trajectory guide marks (405, 406) comprises at least a first line (405a, 406a) that forms a first side of the predicted-trajectory guide mark (405, 406) located on a center side of a vehicle width direction and a second line (405b, 406b) that forms a second side of the predicted-trajectory guide mark (405, 406) located on an outer edge side of the vehicle width direction, the first line (405a, 406a) being separated from the second line (405b, 406b), the superimposing section superimposes a pair of left and right first lines (405a, 406a) of the predicted-trajectory guide marks (405, 406) respectively at positions in an outer edge direction from the tow coupler to display a region between the pair of left and right first lines (405a, 406a) as a predicted-trajectory of the tow coupler, the first lines (405a, 406a) being located on the center side of the vehicle width direction, and the superimposing section superimposes a pair of left and right second lines (405b, 406b) of the predicted-trajectory guide marks (405, 406) respectively as predicted-trajectories of both lateral edges of the vehicle supported by the apparatus, the second lines (405b, 406b) being located on the outer edge side of the vehicle width direction. an image acquiring section that acquires a captured image of an area behind a vehicle supported by the apparatus, the area including a tow coupler at a rear portion of the vehicle and a tow-target coupler of a tow-target vehicle to be coupled to the tow coupler; and a superimposing section that superimposes a pair of left and right planar predicted-trajectory guide marks (405, 406) in accordance with steering operation of the vehicle supported by the apparatus, on the captured image acquired by the image acquiring section and that outputs the superimposed image, wherein each of the pair of left and right planar predicted-trajectory guide marks (405, 406) comprises at least a first line (405a, 406a) that forms a first side of the predicted-trajectory guide mark (405, 406) located on a center side of a vehicle width direction and a second line (405b, 406b) that forms a second side of the predicted-trajectory guide mark (405, 406) located on an outer edge side of the vehicle width direction, the first line (405a, 406a) being separated from the second line (405b, 406b), the superimposing section superimposes a pair of left and right first lines (405a, 406a) of the predicted-trajectory guide marks (405, 406) respectively at positions in an outer edge direction from the tow coupler to display a region between the pair of left and right first lines (405a, 406a) as a predicted-trajectory of the tow coupler, the first lines (405a, 406a) being located on the center side of the vehicle width direction, and the superimposing section superimposes a pair of left and right second lines (405b, 406b) of the predicted-trajectory guide marks (405, 406) respectively as predicted-trajectories of both lateral edges of the vehicle supported by the apparatus, the second lines (405b, 406b) being located on the outer edge side of the vehicle width direction.