To enable an antenna to output electromagnetic wave high in frequency and high in output by providing a switching part which is normally in a close state, makes electric energy by means of an energy amplification/ accumulation part to pass through and generates high voltage pulse by being in an open state when a control signal is given from a control part thereby applying the high voltage pulse to a magnetron.

An MHD explosive generator 10 generates DC voltage. An MC-type explosive generator 20 accumulates current which is amplified while current supplied from the MHD explosive generator 10 is amplified as electric energy. A plasma switch 30 is always in a closed state and can accumulate electric energy by the MC-type explosive generator 20. When a control signal is given, it becomes an open state and generates a high voltage pulse. Thus, the high voltage pulse can be applied to a magnetron 40 and the electromagnetic wave of a high frequency and high output is outputted from an antenna 50. A control part 60 supplies a starting signal and the control signal at prescribed timing.