In order to generate intense compression waves in a molten metal under non-contact operation, a new method has been proposed where a high static magnetic field and a high frequency one are simultaneously imposed on a molten metal. A mathematical model based on the compressible fluid dynamics and the electromagnetic field theory has been developed to derive the pressure distribution in a metal. The intensity of compression waves is indicated as a function of physical properties of a metal and operating conditions. Furthermore, the pressure oscillation caused by compression waves was measured and compared with the theoretical prediction derived by the mathematical model.