An image forming apparatus includes: an image forming unit that forms an unfixed image on a sheet; and a fixing unit that includes a first rotary member and a second rotary member, which are in contact with each other to form a nip part, and that fixes the unfixed image formed in the image forming unit to the sheet by allowing the sheet to pass through the nip part. When a large-width sheet having a larger width than a preceding sheet that has previously passed through the nip part is allowed to pass through the nip part, adjustment in which the first rotary member and the second rotary member are displaced in directions away from each other, while forming the nip part, is performed in the fixing unit.