PURPOSE: To obtain an L.L buckwheat noodle which is the one provided with long-term shelf stability by pH adjustment/heat treatment, lightened in the occurrence of a strange taste and an offensive smell, by using buckwheat flour having a protein content equal to or smaller than a fixed value, preparing dough of buckwheat noodle, pregelatinizing, acidifying, packing, sealing and heat-treating the dough.

CONSTITUTION: Buckwheat flour having ≤5.5%, preferably ≤4.5% protein content as a raw material is optionally mixed with wheat flour, a starch, an alkali agent, salt, a thickening agent and buckwheat chaff powder and kneaded with water to prepare dough of buckwheat noodle. The dough of buckwheat noodle is made into noodle belts/long strips of buckwheat noodle and pregelatinized. The long strips of buckwheat noodle are treated with an acid during or after the pregelatinizing treatment, adjusted to acidic pH, packed, sealed and heat-treated to give the objective L.L buckwheat noodle. The buckwheat flour as the raw material is preferably buckwheat flour from which the epidermis is removed.