Hair is very important in determining human appearance. Although there are numerous observed data and experimental recordings for hair, a detailed mechanism of hair formation has not yet been elucidated. Therefore, in this study, a simulation of the method of formative process of hair roots was done using a 3D particle model. The model contains details of the cell growth from the hair matrix cells and changes from spherical to non-spherical oval shape. Simulation results were able to exhibit the hair formation process from the base of the hair follicle. Furthermore, at the surface opening of the follicle, the hair structure was recorded. Therefore, this model can be used to clarify the mechanism of hair root formation.