Today, the application of digital transformation (DX) for after-sales service in the manufacturing industry is indispensable as a part of the customer experience regarding the product. Mitsubishi Heavy Industries, Ltd. (MHI), a manufacturer of a wide variety of mechanical products, has also focused on improving the customer experience in parts purchasing and has developed E-Commerce for mechanical products. This enables customers to purchase parts anytime and anywhere via the internet. This report describes the customer experience and functions provided by E-Commerce, its architecture, the results obtained, and future prospects.