The invention relates to the technical field of steel scrap smelting, and discloses a waste gas treatment device for iron-containing steel scrap smelting. The device comprises a collecting hopper, wherein a straight flue channel is fixedly mounted at the bottom of the collecting hopper and close to one side, a partition plate is fixedly mounted at the position of one side of the top of the straight flue channel and located in the collecting hopper, and an inductor is fixedly installed at the position, close to the bottom, of one side of the inner wall of the collecting hopper, the top of the inner cavity of the straight flue channel is movably sleeved with a rotating partition plate. According to the invention, a partition plate is fixedly installed at the position, located in a collecting hopper, of one side of the top of a straight flue channel so as to divide the inner cavity of the collecting hopper into two parts by the partition plate, the tops of the two parts communicate with each other, and when a furnace mouth bin door is opened, internal high-temperature airflow flows into the collecting hopper and cannot be in direct contact with an inductor under the blocking effect of the partition plate, so that the problems that high-temperature gas in the furnace directly makes contact with the inductor, the temperature of the high-temperature gas is too high, the high-temperature gas is opened too early or closed too completely, and induction is not sensitive are solved.