A filling apparatus comprising: a plurality of parallel tunnels (12, 12'} formed in a longitudinal body {11, 11') and arranged in a longitudinal direction of said body (11, 11')； and a filler reservoir (20) having an exit end (21) adapted to be in fluid communication with said plurality of parallel tunnels {12, 12'), characterized in that a cross-sectional area of said exit end (21) is less than about 5 times, preferably less than about 3 times, and more preferably about 1.5 to about 1.1 times a total cross-sectional area of said plurality of parallel tunnels {12,12'), wherein the apparatus is configured such that a filler contained in said filler reservoir {20) is driven into said plurality of parallel tunnels (12, 12') via said exit end (21), when said exit end (21) is in fluid communication with said plurality of parallel tunnels (12, 12')； and said plurality of parallel tunnels (12, 12') are separable from said filler reservoir (20) after said plurality of parallel tunnels (12, 12') are filled with said filler.
