To provide a fermenter enabling continuous brewing of a liquid fermented food such as fish soy which has not been attainable through using conventional batch fermenters.

This fermenter has the following structure: at least two compartmental walls 2a and 2b each lower than any of the four surrounding walls of the fermenter 1 and also gradually lowered in height from one end of the fermenter toward the other end threreof, are set side by side in the fermenter 1; at least three of compartmental tanks, i.e., a compartmental tank I at one end of the fermenter, compartmental tanks II and III at intermediate positions and a compartmental tank IV at the other end thereof, are formed in the above fermenter 1; in the compartmental tank I at one end and the compartmental tanks II, III, vertical passages 5a and 5b are formed respectively between in the compartmental walls 2a, 2b and partition walls 4a, 4b respectively set so as to face on the compartmental walls 2a and 2b, and also bottom part passages are formed below the partition walls 4a and 4b; and an extraction port 10 for a matured liquid b is formed on the compartmental tank IV at the other end of the fermenter.