To produce a composite processed yarn in which slub-like entangled portions and substantially non-twisted entangled portions are alternately repeated in the longitudinal direction of the yarn in irregular lengths, and which has a spun-like touch, a projection-like hand touch, and deep black color surface variation, when dyed with a black dye, and is suitable for the use of black formal wears, and to provide a method for producing the same.

This composite processed yarn in which slub-like entangled portions and substantially non-twisted entangled portions that comprise a cation dye-dyeable filament yarn as a sheath yarn are alternately repeatedly formed on a core yarn comprising polyethylene terephthalate filaments in the longitudinal direction of the yarn in irregular lengths is characterized in that the colors of the slub-like entangled portions are deeper than the colors of the substantially non-twisted entangled portions, when dyed with a black dye.