PURPOSE: To produce at mat which can adsorb only the emulsive oil component by suspending vegetable fibers imparted with hydrophobicity in water, releasing pressurized water satd. with air into the water to float the suspended fibers to form a porous fiber layer then dehydrating and drying the same.

CONSTITUTION: The pressurized water sated. with air is released into a liquid such a raw material liquid prepd. by suspending the vegetable fibers preliminarily imparted with hydrophobicity into the water or raw material liquid prepd. by suspending the vegetable fibers into the water in which a hydrophobic material (e.g., hydrophobic silicone resin) is preliminarily dissolved. A large amt. of the microfoam generated by such release is stuck onto the suspended fibers and is floated. After the porous fiber layer is formed on the water surface in the above-mentioned manner, the fiber layer is taken on to a wire net and is dehydrated and dried to produce the emulsion adsorptive mat. The mat contains a large amt. of fine spaces in the inside and can maintain the strength thereof by the hydrogen bond among the constituting fibers. The mat is capable of selectively adsorbing away only the emulsive oil-component.