Disclosed herein is a biomagnetic measurement apparatus capable of visualizing cardiac electrical current distributions with information on the cardiac morphology of a subject. A magnetic field component in the z direction, vertical to the chest surface of a subject, is measured from two directions, front and back of the chest, and then to calculate the current distributions in the two directions and the distributions of the amplitudes of those current distributions. A three-dimensional standard heart model is created from average data on the cardiac morphology obtained from plural healthy subjects. An optimal position of the model is determined using the coordinates of the sinus node and the coordinates of the left ventricle. Then, a weight coefficient is obtained by front and back current distributions and front and back the distributions of the amplitudes of those current distributions on a set boundary of the model.