PURPOSE: To provide the titled crushing agent which exhibits an excellent crushing effect in a short time even at a temp. below the freezing point, comprising calcium carbide as a principal ingredient.

CONSTITUTION: Industrial calcium carbide particles having a grain size of 6,000 cm2/g or below are used. It is preferred to use particles having such a purity that 50W300l of acetylene gas/kg is produced at 20°C under atmospheric pressure when reacted with water. Holes made in a brittle object such as rock or concrete are filled with said calcium carbide particles. Water is added thereto to react the particles with water, whereby the brittle object is crushed. When 5W70pts. hydraulic material such as ultraquick-hardening cement per 100pts. calcium carbide is blended, a crushing agent exhibiting a further excellent effect can be obtd.