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. A mating detection terminal is positioned in the housing to form a detection circuit when in contact with the complementary mating detection terminal. The attachments are inserted and positioned in guide holes formed respectively on the light-emitting device and the light-receiving device, and the optical axes of the pair of light guides and the optical axes of the light-emitting device and the light-receiving device are aligned with each other. The displayed map may contain one or more map objects. The distal end is rotatable by a rotational drive mechanism extending through the shaft to the distal end. A stream read reads sequential data from a stream, and a stream write writes sequential data to a stream.