Rice grains are soaked in water to give a rice-grain soaked liquid to allow the rice grains to absorb water and the entire rice-grain soaked liquid is then charged into a mill to mill the rice grains to prepare finely-divided rice grains containing water absorbed therein and the finely-divided rice grains form a rice paste containing free water present therebetween the finely-divided rice grains in the rice paste can be fine and, in addition, since free water is involved upon milling, deterioration of components by heat can be avoided. In addition, the finely-divided rice grains can remain in a water-absorbed state, and damage of finely-divided rice grains (starch simple grains) by drying can be avoided. In addition, since free water increases affinity between a kneaded product of a different kind of cereal flour or other ingredients and the rice paste, mixing thereof can be rapidly carried out.
