FIBER STRIP BODY MEASURING APPARATUS AND YARN WINDER

PROBLEM TO BE SOLVED: To provide a fiber strip body measuring apparatus for improving foreign matter detection sensitivity by suppressing occurrences of shadow when detecting foreign matters and excellently detecting unevenness in thickness of the fiber strip body.SOLUTION: A clearer includes a light source part 36, a light reception part for functioning as a transmission beam reception part and a reflecting light reception part, and a diffusion member 38. The light source part 36 radiates light to running spun yarn. The light reception part receives light which is radiated by the light source part 36 and passes through the spun yarn. The light reception part also receives light radiated by the light source part 36 and reflected by the spun yarn. The diffusion member 38 is arranged between the light source part 36 and the spun yarn and diffuses light from the light source 36. The diffusion member 38 is larger in degree to which it diffuses light in a flat surface orthogonal to the running direction in comparison with the degree to which it diffuses light in the flat surface parallel to the running direction of the spun yarn.