PURPOSE: To improve exhaust of air inside an electronic apparatus, to eliminate thereby the occurrence of a void and also to optimize the quantity of a molding agent filled up, by a construction wherein an opening of the apparatus for filling up the molding agent is provided at a position below an air vent opening and further a detector for optimizing the quantity of the molding agent filled up is provided in the vicinity of the air vent opening.

CONSTITUTION: A molding agent 12 is filled up in an electronic apparatus 1 by holding a case 2 by an electronic apparatus holding arm 16 and by filling the same from an opening 10 for filling the molding agent provided in the bottom part of the case 2, by means of a dispenser 6 with a rubber cap 11. While discharging the air inside the electronic apparatus 1 from an air vent opening 13 provided in the upper part of the case 2, the molding agent 12 is filled up gradually in every corner of the case 2, beginning with a packaged board 3. When the molding agent 12 rises to the air vent opening 13, subsequently, a limit switch 14 provided at the air vent opening 13 operates to stop filling. Adhesive paper 17 is stuck on the air vent opening 13 to close it up so that the molding agent 12 may not leak therefrom at the time of a subsequent reverse operation.