PROBLEM TO BE SOLVED: To provide a production method of fermented mulberry tea that abundantly includes amino acids and in which ingestion is easy.SOLUTION: A production method of fermented mulberry tea includes a process (A) in which a mulberry leaf in which a moisture content is 25-50%, is inoculated with aspergillus, and the mulberry leaf is left under a condition of 25-45°C for 40-80 hours. In the production method, the aspergillus is suitably aspergillus oryzae and/or aspergillus kawachii, moreover the production method suitably includes a process after the process (A) in which the moisture content of the mulberry leaf is made 40-60% and the mulberry leaf is left under a condition of 45-50°C for 15-80 hours.COPYRIGHT: (C)2014,JPO&INPIT【課題】アミノ酸を豊富に含み、摂取し易い発酵桑茶の製造方法を提供する。【解決手段】本発明に係る発酵桑茶の製造方法は、含水量を25~50%とした桑葉に麹菌を播種し、該桑葉を25~45℃の条件下に40~80時間おく工程(A)、を含むことを特徴とする。前記製造方法において、麹菌がアスペルギルス オリゼー及び/又はアスペルギルス カワチであることが好適であり、また、前記工程(A)後、桑葉の含水量を40~60%とし、45~50℃の条件下に15~80時間おく工程、を含むことが好適である。【選択図】 なし