PURPOSE: To reduce wear, extend life, improve sewing performance, and realize reduction in noise by forming a skin consisting of a material containing a synthetic resin having a specified thickness on the surface in a sewing machine part such as a rotating hook, a rotating hook bobbin case holder, a looper, and a needle thread take-up.

CONSTITUTION: A rotating hook bobbin case holder 1 to be installed to a rotating hook, which is used in a vertical fullrotating hook, has a cylinder part 7, a truck 8 formed on the outer circumference, a flange part 10 having a rotating hook case holder position bracket recessed part 9 formed on the opened-side end part of the cylinder part 7, and a bottom part 11 formed on the other end part of the cylinder part 7. The truck 8 of the rotating hook bobbin case holder 1 is fitted to a truck groove formed on the outer circumferential surface of the rotating hook. In the rotating hook bobbin case holder 1, a skin formed of a material containing a synthetic resin having at least a thickness of 50μm or more is formed on the surface of a rotating hook bobbin case holder body formed by casting a material such as stainless steel or steel. As the material of the skin, a material in which metal powder or carbon fiber is dispersed in a synthetic resin such as fluororesin is preferably used.