The invention aims to provide a chain component having a simple surface treatment structure and capable of maintaining excellent abrasion resistance over a long period, and a chain including the chaincomponent and capable of maintaining excellent abrasion resistance elongation. A chain component of a chain (1) for industrial power transmission comprises a chromium nitride layer provided outside asteel-based substrate and containing iron more than 0 mass% and equal to or less than 55 mass %. At least a surface of the chromium layer sliding on other components is a rough surface with irregularities.