PURPOSE: To produce a soundproof material in a simple step with good moldability.

CONSTITUTION: This method for producing a soundproof material comprises (a) the step of adding a pH adjustor to an aqueous slurry containing a high- specific gravity filler, (b) the step of mixing the resultant slurry with a water- crosslinkable urethane prepolymer, (c) the step of shaping the slurry containing the urethane prepolymer into a prescribed form, (d) the step of allowing the shaped material to stand and thereby gelatinizing the shaped material and (e) the step of drying the gelatinized shaped material.