Novel microwave processing equipment includes a silicon single crystal containing neutral {110} planar four vacancies, a cooling mechanism for holding the silicon single crystal to a low temperature, a light pumping mechanism for irradiating light to the silicon single crystal, a magnetic field applying device for applying a static magnetic field to the silicon single crystal, an orientation holding mechanism for holding the silicon single crystal to a specific orientation with respect to the static magnetic field, an electromagnetic wave inputting mechanism for supplying an input electromagnetic wave to the silicon single crystal, and an electromagnetic wave outputting mechanism for extracting an output electromagnetic wave from the silicon single crystal. The input electromagnetic wave supplied in the silicon single crystal by the electromagnetic wave inputting mechanism is amplified by the stimulated emission produced in the silicon single crystal and passes through the electromagnetic wave outputting mechanism to be outputted to the outside. A microwave amplifier with narrow band width capable of amplifying the electromagnetic wave in the microwave range with low noise is thus obtained.