An image forming apparatus including an image forming unit; a pair of frames that faces each other with sandwiching the image forming unit therebetween, at least one of the pair of frames including: a first frame, which is made of resin, and which forms a lower part thereof; and a second frame, which forms an upper part thereof; a duct that forms an air passageway between an outer side of the pair of frames and an inner side of the pair of frames; a fan that generates airflow in the duct; and a rib wall, which forms at least a part of the duct, and which is integrally molded with the first frame, wherein a width of the rib wall, increases from an upper end side of the first frame to a lower end side of the first frame.