Abstract: A method of crushing or smashing nonconductive materials such as natural ore materials and concretes by a discharge voltage requires a large amount of energy for crushing or smashing. Products produced by crushing or smashing have not been recycled effectively as new nonconductive raw materials. A value set by the quality and a thickness of the nonconductive materials to be crushed, an impulse voltage Uo, a time constant .tau. and a spark constant A is defined as a parameter P of an electric circuit. By setting the value of P to 0.02.ltoreq.P.ltoreq.1.0 to cause crushing, energy stored in the circuit can be utilized effectively. Accordingly, uniformcrushedor smashed matter with high quality can be manufactured effectively.