PURPOSE: To obtain inexpensive, high-quality potassium titanate fibers which cannot be obtained by conventional production methods.

CONSTITUTION: Firstly, potassium compound powder and titanium compound powder are kneaded with a substance imparting the powder with fluidity to prepare a stock admixture. Second, this admixture is molded and baked to obtain a porous baked form consisting of the objective potassium titanate fiber assembly. By making the stock powder into a molded form, stock handleability in the baking process can be improved; besides, separation of the baked form into fibers can be facilitated. The crystalline fibers thus obtained are greater in both fiber length and fiber diameter than those fibers obtained by conventional production methods, also being smaller in variation.