Abstract: Blasting devices, each comprising an explosive substance, a deflector, and a casing containing an incompressible fluid, the explosive substance, and the deflector are inserted into respective holes bored in a rock or the like at spaced apart positions, a tamper being thereafter stuffed in each hole, and the explosive substances in the holes are detonated simultaneously. A shock wave or blast wave is thus created in the incompressible fluid in each hole, and is deflected by the deflector in a direction along which the rock or the like is to be fractured. An improved construction of the blasting device for practicing the method is also provided.