Brain damage by the impact force was evaluated by the numerical analysis with a three dimensional Finite Element (FE) model. The FE model was constructed from the MRI data of a subject, and visco-elastic behavior for constitutive equation was applied to the brain tissue. From the FE simulation, brain damage and deformation of the frontal head impacted by a steel impactor were analyzed. The variations of head acceleration and Intra-Cranial Pressure (ICP) during the impact were analyzed in order to evaluate Traumatic Brain Injury (TBI). In addition, relative displacement between the skull and the brain due to head impact was investigated. And, pathological severity was evaluated according to Head Injury Criterion (HIC) from the FE simulation. The analytic results of brain damage showed a good agreement with those of the cadaver test performed by Nahum et al. (1977) and other medical reports. And then, the variation of the HIC value was evaluated according to various impact conditions. This study would provide useful data and methodology in the field of biomechanics for analyzing the brain damage by head impact.