To provide a summer clothing yarn giving fresh and cool feel, which has not been sufficiently achieved with a conventional technique on yarn thickness.

A cooling yarn is synthesized from a mixture of a liquid nylon yarn, a liquid tetoron yarn, and solid nitrogen in a liquid state. The synthesized yarn of the liquid nylon yarn and the liquid tetoron yarn includes a yarn synthesized from a mixture of plant fiber bamboo grass stems and leaves and a cooling yarn synthesized from a mixture of rice stems and leaves, having a gloss due to the presence of the plant fiber fragments. A light weight yarn is synthesized from the designed yarn with a gloss due to the plant fiber in fragment shape and a tetoron yarn containing weed ash.