PURPOSE: To obtain a liquid mildewproofing agent composition having ready handleability and excellent safety, rapidly removing molds, consisting essentially of an abradant, a surfactant and a neutral mildewproofing agent having permeability.

CONSTITUTION: For example, (A) 30wt.% abradant comprising fine powder or granules such as sand or silica gel is blended with (B) 30wt.% liquid neutral mildewproofing agent having excellent permeability, preferably silicone-based mildewproofing agent, (C) 7wt.% surfactant and (D) 33wt.% other components and stirred to give the objective liquid mildewproofing agent. The ratio of the component A and the component B is preferably approximately equal.