The subchondral bones and the articular cartilages constituting the joint parts in biological hard tissues have shock absorbing capabilities as bones strike each other at the joints. In order to clarify this phenomenon, acrylic plates of a porous medium of different diameters were modeled to represent these articular cartilages. In the experiment, when these models are impacted with different impact velocity, the reduction effect of shock waves which pass through the pores is measured using strain gages. It is found from the results of these experiments that when shock waves pass through the pores of a model, shock-absorbing effects, especially as regards maximum stress and duration times, appear. Moreover, the same results are obtained by applying the one- dimensional wave theory and the dynamic finite-element method to these models.