To evaluate the the increment of the density under the vibratory roller treatment for very stiff concrete in fresh condition, laboratory cyclic-loading tests were conducted for the small specimen. And it was found that the dentification could be occurred with the loading. When the cyclic shear stress of high amplitude was loaded under undrained condition, the value of pore pressure increased and resulted to failure. The relationship between the increment of density and the number of loading could be simulated as the hyperbolic line defined with the initial density and the loading amplitude. With this hyperbolic model, the increment of density in the field treatment could be predicted.