To appropriately support the diagnosis of auxocardia on the basis of a cardiothoracic ratio measured from an image of the thorax of a subject for diagnosis and the same measured from an image of the thorax of the past.

When the cardiothoracic ratio A of the image of the thorax of the subject for diagnosis is lower than a predetermined threshold value B (Step S15:YES) and is equal to or higher than a predetermined threshold value C (Step S16:YES), the diagnostic imaging support apparatus inquires examinations in the past of an image server device (Step S17). The diagnostic imaging support apparatus acquires the results of cardiothoracic ratio measurement carried out D times in the past from the image server device (Step S19), computes a reference value for the past by calculating a weighted average of the values and computes a decision value F by taking into account the difference between the current cardiothoracic ratio A and the reference value for the past and the current cardiothoracic ratio A (Step S20). When the decision value F is greater than a standard value E (Step S21:YES), the apparatus displays an indicator in a display section (Step S22).