The aim of our work is to visualize three-dimensional (3-D) images of atrial excitation. We obtained these images by projecting the anterior and posterior current-arrow map (CAM), derived from a magnetocardiogram (MCG), onto a 3-D standard heart model. We generated the projected CAM (PCAM) of early and late atrial depolarization phases for fourteen healthy subjects. During early and late atrial excitation, the high-current areas of all subjects were in the right atrium of the anterior surface, and the left atrium of the posterior surface. The averaged ratio of the maximal current value of the early p-wave to the maximal current value of the late p-wave for all subjects was 0.9 ± 0.2. Furthermore, the averaged maximal current directions of the early and late p-wave were 78 ± 15 and 165 ± 17 degrees, respectively. Thus, we found that the PCAM could provide separated images of the left and right atrial excitations.