To provide reinforcing structure and method for a protective fence prop for reinforcing not only an existing protective fence prop but also a new protective fence prop easily and increasing the strength of the protective fence props to cope with external force generated at vehicle collision time.

An L-shaped reinforcing fitting 1 is attached to the protective fence prop 10 by fixing it to a base plate 3 to reinforce a part close to a lower end of a prop body 2 being the most likely to deform by the reinforcing fitting 1 when such external force that causes plastic deformation is applied to the prop body 2 when a vehicle collides against the protective fence prop 10 and increase the strength of the protective fence prop 10 in order to cope with the external force generated at the vehicle collision time. Since the reinforcement of the protective fence prop 10 becomes possible owing to attaching the reinforcing fitting 1, the protective fence props 10 including not only the existing protective fence prop but also new protective fence prop can be easily reinforced.