In a maintenance management system and a method of providing engineering support, maintenance information concerning generating plants owned by a user is provided to a maker, and the maker analyzes such items of information, and manages the information in a structure maintenance management system. The user accesses the maintenance management system through the Internet, extracts information to be obtained from databases, and implements maintenance activities or drafts a plan. Engineers of the maker register maintenance information through an intranet, and provide engineering support for the maintenance activities promoted by the user.