A process for producing a purified product of green tea extract, which includes subjecting an aqueous solution of green tea extract to solid-liquid separation by filtration and/or centrifugal separation to obtain another aqueous solution of green tea extract, said another aqueous solution having a turbidity of from 0.2 to 2.0 as measured with a concentration of non-polymer catechins in it adjusted to 1 wt %, and then allowing the another aqueous solution of green tea extract to pass through a polymer membrane having a membrane pore size of from 0.05 to 0.8 .mu.m such that the turbidity of the another aqueous solution of green tea extract is reduced to lower than 0.2 as measured with a concentration of non-polymer catechins in it adjusted to 1 wt %.