This paper investigates the roles and effects of dynamic absorbers attached to the leg frames on the gait properties of passive dynamic walking. First, we model a passive compass-like biped robot that consists of two identical leg frames with passive dynamic absorbers that represent micromechanical vibration or human flesh dynamics. Second, we conduct gait analysis through numerical simulations to observe how the small oscillation of the leg frames affects the gait properties. The simulation results show that the generated walking gait is nonlinearity. Furthermore, we mathematically model the dominant effect of the dynamic absorbers which represents the micro vibration the metal leg frame produces by using an input-output linearization.