Waste gas treatment device

The waste gas treatment device comprises a first box body, a second box body, a third box body and a draught fan, the first box body is provided with a containing cavity, and a first gas inlet and a first gas outlet which communicate with the containing cavity are formed in the two opposite side walls of the first box body correspondingly; the second box body, the third box body and the fan are arranged in the accommodating cavity, and a second air inlet communicated with the first air inlet is formed in the side wall, facing the first air inlet, of the second box body; the third box body is located on one side of the second box body, a second air outlet is formed in the side wall, facing the third box body, of the second box body, a third air inlet is formed in the side wall, facing the second box body, of the third box body, the third air inlet is communicated with the second air outlet, and a third air outlet is formed in the side wall, away from the second box body, of the third box body. And the fan is l