The torsional vibration hinders the reduction of automobile exhaust gas emitted by using engines with a reduced number of cylinders. Centrifugal pendulum vibration absorbers (CPVA) have been used in engines to suppress torsional vibration. To clarify the dynamics of CPVAs, much analysis has been conducted using the point mass CPVA as the model of rigid body bifilar CPVA. However, few attempts have been made to analyze the rigid body unifilar CPVA on vibration suppression performance in frequency response. In this study, the authors have analyzed the dynamics of the rigid body unifilar CPVA, focusing on the influence of shape parameters. The results verified that the shape parameters, which relating to moment of inertia or radius of gyration of rigid body unifilar CPVA, influence the vibration suppression performance in frequency response. Moreover, the numerical simulation results were confirmed experimentally and showed in good agreement with the experimental results, and both indicated the dependence of the vibration suppression performance on the shape parameters of the rigid body unifilar CPVA.