A gas burner apparatus (100, 100', 100") comprising: a first burner (110, 210) to receive supplied gas mixed with a first primary air from a first primary air supply flow path and to inject flames through a plurality of first burner ports (112, 112') of the first burner (110, 210); a second burner (130, 230), spaced apart from a lower side of the first burner (110, 210), to receive the supplied gas mixed with a second primary air from a second primary air supply flow path and to inject flames through a plurality of second burner ports (135, 137) of the second burner (130, 230); a support plate on which the second burner (130, 230) is disposed; and a secondary air supply flow channel (S1, S2) to supply secondary air to the first burner (110, 210), the secondary air supply flow channel (S1, S2) including a first secondary air supply flow path formed between the first (110, 210) and second burners (130, 230) and a second secondary air supply flow path starting from an area lower than the support plate, the first and second paths being connected to each other, characterized in that the first burner (110, 210) comprises a mixture gas supply pipe (111a, 111a", 131a) to supply the supplied gas and that is formed sequentially through the second burner (130, 230) and a through hole of the support plate; and the through hole of the support plate has an inner circumference surface that is spaced apart from an outer circumferential surface of the mixture gas supply pipe (111a, 111a", 131a), wherein the support plate is coupled to a shielding rib that extends toward the first burner (110, 210) from the through hole of the support plate. a first burner (110, 210) to receive supplied gas mixed with a first primary air from a first primary air supply flow path and to inject flames through a plurality of first burner ports (112, 112') of the first burner (110, 210); a second burner (130, 230), spaced apart from a lower side of the first burner (110, 210), to receive the supplied gas mixed with a second primary air from a second primary air supply flow path and to inject flames through a plurality of second burner ports (135, 137) of the second burner (130, 230); a support plate on which the second burner (130, 230) is disposed; and a secondary air supply flow channel (S1, S2) to supply secondary air to the first burner (110, 210), the secondary air supply flow channel (S1, S2) including a first secondary air supply flow path formed between the first (110, 210) and second burners (130, 230) and a second secondary air supply flow path starting from an area lower than the support plate, the first and second paths being connected to each other, characterized in that the first burner (110, 210) comprises a mixture gas supply pipe (111a, 111a", 131a) to supply the supplied gas and that is formed sequentially through the second burner (130, 230) and a through hole of the support plate; and the through hole of the support plate has an inner circumference surface that is spaced apart from an outer circumferential surface of the mixture gas supply pipe (111a, 111a", 131a), wherein the support plate is coupled to a shielding rib that extends toward the first burner (110, 210) from the through hole of the support plate.