For the effective and early diagnosis of brain diseases, we have developed an evaluation system for brain function using an Independent Component Analysis (ICA) method. This evaluation system benefits greatly from the newly emerged Grid. To embody a Grid environment, a Globus grid toolkit has been utilized as a building block. In this research we have distributed the computational workload for the ICA on a Globus based Grid environment composed of two Alpha cluster systems and a personal computer. In addition, in order to allow scientists and application developers to easily build the Grid-enabled system, we also have adopted a Grid-enabled-Message Passing Interface, called MPICH-G. An introduction of MPICH-G to the medical analysis system on a Grid environment makes it possible for a na?ve user to realize rapid analysis without special knowledge of the Grid. Magnetoencephalography (MEG), a highly sophisticated medical technology, is used for the measurement of brain function. The proposed method has the ability to integrate various geographically distributed resources and to analyze functional brain data from MEG