To provide a medical image processor and medical image processing program for presenting in a short period of time, information to correctly identify a site of earliest activation by acquiring the distribution of endocardial currents generated by excitation.

The medical image processor includes a data acquisition means and a data processing means. The data acquisition means acquires a magnetic field distribution in the heart of a subject and morphologic image data of the heart. The data processing means obtains distribution of current densities in the heart on the basis of the magnetic field distribution and the distribution model of current densities in the heart which is based on the morphologic image data.