A diagnosis support apparatus which provides information for supporting medical diagnosis obtains known medical information of a diagnosis target held in a database as “already-input” information, and has a selection unit that selects non-input information to be presented as medical information, other than the already-input information. A similar-case obtaining unit obtains, using the already-input information and the presentation non-input information, a case including the presentation non-input information from a case database, as a case similar to that of the diagnosis target, and a presentation unit presents the presentation non-input information and the similar case.