A mounting structure wherein a buffer member has a body portion, and a leg portion which is extended from the body portion and engaged with a recess, wherein the body portion has a plurality of first convex portions which are arranged around a center axis of the body portion at regular intervals and abut against a vehicle body, a plurality of first concave portions each of which is formed between the adjacent first convex portions, a plurality of second convex portions which are arranged around the center axis of the body portion 61 at regular intervals and abut the fuel tank, and a plurality of second concave portions each of which is formed between the adjacent second convex portions, and wherein the first convex portion is formed corresponding to the second concave portion, and the second convex portion is formed corresponding to the first concave portion, is provided.