An apparatus for preventing contamination of roll surface and strip edge bulging in a twin roll strip caster which includes a meniscus shield 5 for interrupting inflow of external air while feeding non-oxidizing gas to prevent oxidation of molten steel in a molten steel pool 13 defined by casting rolls 1 and 1a and edge dams 4 and a plurality of weirs 12 mounted under the meniscus shield 5 for preventing mold level fluctuation, the apparatus comprising: first chambers 60 arranged at both sides of the meniscus shield 5 in a longitudinal direction parallel to the casting roll 1 and having inlet and outlet ports for non-oxidizing gas; and second chambers 80 each assembled to an underside in each of the first chambers 60 in a communicating fashion for receiving non-oxidizing gas from the first chambers 60, and including a plurality of holes 81 formed in an inclined face thereof corresponding to an outer peripheral face in each of the casting rolls 1 and 1a in a longitudinal direction of the each casting roll 1 or 1a; and passages S formed between the meniscus shield 5 and the second chambers 80 and reaching the gas outlet ports of the first chambers and wherein the gas inlet and outlet ports include: upper gas inlet ports 61 perforated in upper faces of the first chambers 60 and connected to a gas feed line 61a for feeding non-oxidizing gas; upper gas outlet ports 62 perforated in upper faces of the first chambers 60 connected to a gas exhaust line 62a, wherein the upper gas inlet and outlet ports 61 and 62 are separated via a plurality of partitions 63; lower gas outlet ports 64 in the undersides of the first chambers 60 corresponding to the upper gas inlet ports 61; and lower gas outlet ports 65 in lateral portions of the first chambers 60 corresponding to both lateral portions of the meniscus shield 5. first chambers 60 arranged at both sides of the meniscus shield 5 in a longitudinal direction parallel to the casting roll 1 and having inlet and outlet ports for non-oxidizing gas; and second chambers 80 each assembled to an underside in each of the first chambers 60 in a communicating fashion for receiving non-oxidizing gas from the first chambers 60, and including a plurality of holes 81 formed in an inclined face thereof corresponding to an outer peripheral face in each of the casting rolls 1 and 1a in a longitudinal direction of the each casting roll 1 or 1a; and passages S formed between the meniscus shield 5 and the second chambers 80 and reaching the gas outlet ports of the first chambers and wherein the gas inlet and outlet ports include: upper gas inlet ports 61 perforated in upper faces of the first chambers 60 and connected to a gas feed line 61a for feeding non-oxidizing gas; upper gas outlet ports 62 perforated in upper faces of the first chambers 60 connected to a gas exhaust line 62a, wherein the upper gas inlet and outlet ports 61 and 62 are separated via a plurality of partitions 63; lower gas outlet ports 64 in the undersides of the first chambers 60 corresponding to the upper gas inlet ports 61; and lower gas outlet ports 65 in lateral portions of the first chambers 60 corresponding to both lateral portions of the meniscus shield 5. upper gas inlet ports 61 perforated in upper faces of the first chambers 60 and connected to a gas feed line 61a for feeding non-oxidizing gas; upper gas outlet ports 62 perforated in upper faces of the first chambers 60 connected to a gas exhaust line 62a, wherein the upper gas inlet and outlet ports 61 and 62 are separated via a plurality of partitions 63; lower gas outlet ports 64 in the undersides of the first chambers 60 corresponding to the upper gas inlet ports 61; and lower gas outlet ports 65 in lateral portions of the first chambers 60 corresponding to both lateral portions of the meniscus shield 5.