PURPOSE: To directly recover excess impregnating liq. adhered to a body to be impregnated in an impregnation tank and to effectively reuse the liq. by fitting a centrifugal separator to the tank or a lid for the tank.

CONSTITUTION: A body 2 to be impregnated is fixed in the basket 4 of a centrifugal separator 3 and an impregnation tank 1 is hermetically sealed by lowering a lid 5 for the tank 1. A vacuum pump 10 is worked to evacuate the tank 1 and a storage tank 6 contg. an impregnating liq. 9. The tank 6 is lifted up to a position above the tank 1 to transfer the liq. 9 to the tank 1 until the body 2 is immersed in the liq. 9. The vacuum state of the tank 1 is broken and the air is introduced into the tank 1 to force the liq. 9 into the cavity in the body 2. The tank 6 is then lowered to the original position to recover the excess liq. 9 in the tank 6 and the motor 13 of the separator 3 is worked to separate the liq. 9 adhered to the surface of the body 2 or the liq. 9 penetrated into a working hole. The separated liq. is also recovered in the tank 6.