The present invention relates to a safety device which is used for a guide pipe and a leading needle component, the safety device is provided with a spring clamp (50), the spring clamp is provided with at least one first clamping part (52), at least one second clamping part (55) and a catch (53), when the leading needle is drew out, the first clamping part is irreversibly meshed with a first clamped part (47) which is arranged on a needle cage (40), the catch (53) moves to the position in front of the distal end of the leading needle, and a limit device (80) can limit the distal end of the leading needle 31 not to move to the outside of the needle cage. The safety device of the present invention can prevent the reuse of the spring clamp, the needle cage or the components.
