An object of the invention of the present application is to provide a V-shaped groove block for an optical fiber which has a simple structure, and can high strength fusion splice between optical fibers; in order to achieve the object, the present invention provide a V-shaped groove block for optical fibers for aligning and positioning the axis of naked optical fibers, wherein a thin film comprising a material that will not damage the naked optical fiber even when they are slid thereon, is provided on a surface of a V-shaped groove.