The Japanese silk industry has been attempting to produce super-thin or super-thick raw silk, making the most of thin or thick cocoon filaments, respectively, in order to meet the demands of consumers seeking new types of silk products. We used customer assessors and the Kawabata Evaluation System (KES) to investigate the customer’ preferences for thin and thick silk fabrics made from super-thin and super-thick raw silk, respectively. We made a thin fabric from 10d raw silk reeled using very thin filaments from Hakugin cocoons and a thick fabric from 100d raw silk produced by very thick filaments of the Ariake cocoons. The Japanese Industrial Standard silk fabric (JIS L 0803) was used as a control. A sensory test that analysed the human sense of touch showed that there was a significant difference among the 3 fabrics in terms of “softness”, "smoothness", "luster" and "preference" and that thin fabrics were preferred. Our results suggested that the gender and the age of the customer also influenced the results. The KES results revealed that, for thin fabric, the values for Koshi and Hari were small and that for Shinayakasa, which means the fabric's softness, were large. Our study showed that consumers prefer soft and smooth thin fabrics with luster.