To provide a method for fermentative bread yeast, comprising fermenting a budding yeast and a low temperature fermenting lactobacillus growing in fruits or vegetables by using the fruits or the vegetables themselves as culture media.

The method for fermenting natural bread yeast comprises tightly enclosing 60 to 80 vol.% of fruits or vegetables in a tightly enclosable container, repeatedly lightly shaking the container for 7 to 20 days at 2 to 6°C once per two days so that the juice is uniformly spread and so that the fruits or vegetables are not collapsed, and then storing the contents at 20 to 26°C for 2 to 10 days.