According to the present invention a miso with good flavor and a processed food containing the miso are provided, wherein the miso and the food are expected to have an repressing effect on an increase in blood pressure or hypotensive effect by continually taking the miso or food for routinely dietary habit. The present invention also provides a method of producing a miso, wherein peptides with ACE inhibitory activity are effectively produced in the miso without lowering the quality in flavor of miso. In an embodiment of the present invention, animal milk is added at a content of 10% during a mixing step, or a fermentation and ripening step.