PURPOSE: To improve impregnation, to shorten the impregnation step sharply, and to improve the productivity suitable for mass production, by pressure impregnation of an evacuated article in a liquid cooled at a given temperature.

CONSTITUTION: The synthetic resin liquid 12, e.g. polyethylene glycol dimethacrylate, is stored in the tank 13 under cooling. The article 2 in a container is charged into the tank 1 by the carrying means 19A, and the tank is closed. The cacuum pump 6 is driven to evacuate the tank 1. The liquid 12 is sucked and filled into the tank 1, and the pressure is returned to normal one. The tank 1 is then pressurized by the air compressor 7 at a given pressure to impregnate the article 2 with the liquid 12.