An image forming apparatus including an image bearing member which bears a toner image; a transfer unit which transfers the toner image on the image bearing member to a transfer portion when applied with transfer voltage; a recording material feeding unit which includes a stacking portion where recording materials are stacked and an air blowing device for blowing air to the recording material stacked in the stacking portion, and feeds the recording material to the transfer portion; and a transfer bias control portion which controls the transfer bias according to at least one of air received time per one sheet by the air blowing unit, air pressure and air temperature is provided.