To provide a microwave irradiation method for efficiently increasing functional components contained in raw plants, such as leaves and rhizomes, and to provide raw leaves and rhizomes with increased specific functional components.SOLUTION: Specific functional components peculiar to raw leaves and rhizomes can be increased by irradiating 1 to 100 W, preferably up to about 50 W microwave while controlling the internal temperature of raw leaves and rhizomes to 10-50°C, preferably 30-50°C to activate enzymes in raw leaves and rhizomes. Thereby, raw leaves and rhizomes with increased specific functional components are obtained.SELECTED DRAWING: Figure 1【課題】生の植物、例えば葉や根茎中に含まれる機能性成分を効率的に増加させるマイクロ波照射方法、および特有の機能性成分が増加した生葉や根茎を提供する。【解決手段】生葉や根茎の内部温度を１０～５０℃、好ましくは３０～５０℃に制御しながら、１～１００Ｗ、好ましくは最大約５０Ｗのマイクロ波を照射することにより、生葉や根茎内の酵素を活性化して、生葉や根茎に特有の特定の機能性成分を増加させることができる。これにより、特定の機能性成分が増加した生葉や根茎が得られる。【選択図】図１
