A fluid konjak material, which can be mixed with any other edible material uniformly at a high concentration while sufficiently keeping the gelling power and the biological effect intrinsic to konjak mannan, is provided by swelling and dissolving konjak flour in water, treating the resultant with alkali at a pH of at least 10, lowering the pH to less than 8, heating the composition with forced stirring and enzymatically treating the forcedly-stirred composition.