A design assistance tool, which assists a design of at least one process, defines a metamodel using at least one metaclass, performs a design of the at least one process using the metamodel, stores a content of the design in a database as a design content, displays the design content as a view on a display, and performs creation, modification, or deletion of at least one of the metamodel or a design result based on the metamodel using the view on the display. The view on the display includes multiple view types described in different formats. When the creation, modification, or deletion of at least one of the metamodel or the design result based on the metamodel is made using one view type, corresponding design information is stored in the database, and the creation, modification, or deletion is reflected in another view type based on the stored design information.