Abstract: Rock breaking apparatus includes a guide column within which a weight falls under gravity to strike a tool. A piece of shock-absorbing material is located at or near the base of said column such that it enables force to be transmitted from said weight to the tool, while minimizing the effect of the impact of said weight on other parts of the apparatus. The piece of shock-absorbing material has an aperture therethrough, for the passage of the tool. The tool may have a recessed portion which co-operates with a retaining pin located substantially at right angles to the direction of motion of the tool. The apparatus may also have an operating device, including a device for raising a weight, a device for holding a weight in one of a number of positions and a device for allowing said weight to fall.