A shock absorber mounted on a vehicle includes an inner portion that is made of a metal and has a first upper end and a first lower end, and an outer portion that is made of a composite material and is integrally formed with the inner portion. The outer portion has at least one of a second upper end on which the first upper end of the inner portion is folded and a second lower end on which the first lower end of the inner portion is folded, and a middle portion that has a seat for supporting a suspension spring.