We propose a method to observe cardiac beat from 3-D shape reconstruction by using the grid-based active stereo. In this study, we report preliminary experiments to evaluate validities of the proposed method. As the result of comparing experiments by our method and electrocardiogram (ECG), we confirm sufficient correspondences between the two peak intervals. Our method realizes the separate extraction of cardiac beat and respiratory movement. We try the visualization of cardiac beat by using the color mapping of the depth displacement plotted on the 3-D surface rendering of chest. And, the depth change and the spatial phase difference caused by cardiac pulsation is found on the chest region.