Stitch skip equipment of chain stitch sewing machine

A trace slip stitch device of chain sewing machine of this invention is suitable for the chain sewing machine including following units: a curved needle that swings along the direction parallel to the cloth transporting direction and utilizes a knife tip to capture sewing thread loop from the sewing needle moving up and down, then passes through the curved needle thread to enable the curved needle thread to pass through; a keeper curved needle part whose keeper curved needle pin can form the loop when capturing the curved needle thread from the knife tip of the curved needle; and a curved needle keeping mechanism that can adjust the quantities of support and oscillating of the curved needle, including: an upper support block capable of fixing the curved needle; an actuator that provides the driving force to shift the upper support block; and a lower support block whose one side is provided with the actuator and the other side is connected to a swinging shaft that provides the driving force to enable the curve