A safety fence support device with flexibility may be provided. More particularly, a safety fence support device with flexibility may be provided which is simply installed on a safety fence used in various sports facilities, e.g., a baseball field, an ice hockey rink, a ski slope, etc., causes the safety fence to be tilted backward even when players playing a game or people enjoying the sports in the sports facilities collide with the safety fence at various angles, thereby preventing injury by mitigating impact applied to a human body through the safety fence, and is used in various sports facilities regardless of the kind of the safety fence by controlling the degree of flexibility for mitigating the impact in accordance with the impact strength.