Strong rainfall events may trigger hazardous rockfall on a steep slope. Meteorologists assume that extreme precipitation events are likely to increase in the future elsewhere in the world. Protection authorities now believe that the number and severity of rockfall will increase and the suitable mitigation will be required for roads and railway lines. Protection against rockfall is also required for existing houses. In this study, a new type of rock-fence constructed out of the concrete-filled steel tube with excellent load-carrying capacity and ductility, wire-ropes and wire netting will be introduced. Collision tests were executed by a falling and rolling RC-block impacting against the fence located at the end of the natural steep slope of an angle 41o. The performance of energy-absorption devices that are effective in preventing wire-ropes from breaking was studied and the bending strength and ductility of posts was examined. In order to measure the acceleration of a RC-block falling and rolling down a steep slope, the new system of measuring instruments was also developed.