Image data of various kinds of components and component text data required for mounting of components, e.g., shapes, dimensions, packing forms, colors, and the like of the components, are stored in a storage medium in a manner to be read out as part of a component electronic catalog. The storage medium is used to make a search for components on a screen and automatically read out necessary component text data. The component electronic catalog can be used not only to search for components on a screen, similar to a conventional component electronic catalog, but to automatically read out component text data so as to automatically form mounting data for components to be mounted which are selected through the screen search.