A myocardial excitation complementation/visualization apparatus includes an acquiring section that acquires intracardiac electrocardiograms of a subject, the intracardiac electrocardiograms being recorded by a recording unit having a plurality of electrodes, a processing section that performs a computation for completing and visualizing a state of excitation in a myocardium of the subject based on the intracardiac electrocardiograms, and a displaying section that displays the state of excitation in the myocardium of the subject based on an output of the processing section. The processing section includes a first generating section, a correcting section, a second generating section, and a third generating section. The displaying section displays a change of the state of excitation in the myocardium of the subject based on the visualized data.
