The Japanese Specification for Highway Bridges requires the installation of unseating prevention device on bridges identified as necessary. Recently, a new type of cable restrainer was developed, whose assembly allows the cable to rotate and creates no restriction to their brackets' mounting angle. Cylindrical rubbers are inserted around pins to absorb impact forces. However, no standard design method of the shock absorber has been established yet. This paper presents the study of the impact resisting characteristics of the pin-fixed cable device with a goal of developing the appropriate design method of the shock absorbing rubbers by conducting impact load tests on bracket models of the actual restrainers. As a result, it was observed that pin fixed restrainer has sufficient impact resistance and that there are some trends with maximum impact load. We have also conducted FE analyses on the device assuming the hyperelastic behaviour of three-parameter Mooney-Rivlin model. The analyses could nearly demonstrate the impact response trend obtained from the conducted experiments.