PURPOSE: To fill a moistureproofing mixture in a moistureproofing mixture container formed in a simplified manner, using a self-adhesive foaming polypropyrene sheet such that this sheet is allotted to a cable core exposure portion as the occasion demands but not using cable-size halved hard plastic casings.

CONSTITUTION: A straightforward sausage-shaped bag body 53 is formed by causing a spacer net, in which is contained in a wound condition a bundle of cable core wires exposed with their outer covering being peeled off, to be surrounded by a self-adhesive foaming polypropyrene sheet with a gap therebetween, causing two, up positioned, opposing sheet ends to contact with each other and be opened as a charging port 4 at their central portion but be bonded together at their entire peripheral portions to thereby cause the sheet to be shaped like a bag, and causing both side portions orthogonal to the axis to be constricted onto the cable 1 and be fixed by fastening bands. This bag body is made a moistureproofing mixture container. Then, the charging port is gripped and the mixture is charged therefrom.