The present invention aims to provide a method and an apparatus for producing a lyophilized body, each of which can achieve energy saving, low cost, and a reduction in processing time and can provide a lyophilized body less damaged by a freezing process and a drying process. The present invention relates to a method for lyophilizing a substance using an electromagnetic wave, and the lyophilization method includes freezing the substance under irradiation of at least an electromagnetic wave and reduced-pressure drying the frozen substance under irradiation of at least an electromagnetic wave.
