An image forming apparatus includes an apparatus body, an image forming device to form an image on a recording medium, a casing to accommodate the image forming device, a sheet discharging port through which the recording medium having the image is discharged from the casing, a sheet stacker to stack the recording medium output through the sheet discharging port and opening on one side of the apparatus body and surrounded by outer walls including an outer wall having the sheet discharging port, an air guide opening disposed within a sheet passing range in a width direction of the recording medium in a sheet conveying path through which the recording medium having the image passes from the image forming device to the sheet discharging port, and an air suction fan to discharge air passing through the air guide opening to an outside of the casing.