In a sewing machine for covering chain stitch according to the present invention, a thread push member is mounted on a top cover shaft which drives a cover thread looper, and the thread push member is arranged on the cover thread guide. When swinging backward in association with a movement of the cover thread looper, the thread push member pushes the top cover thread passing through a guide hole of the cover thread guide, forcibly moves the top cover thread and keeps the top cover thread near a back end of the guide hole. The top cover thread is arranged at a predetermined position on a surface of a cloth without being affected by a force from the needle thread, and a covering chain stitch can stably be formed with the excellent appearance.