The image forming apparatus includes: an image former which, upon receiving a first instruction, feeds a sheet and performs an image forming operation to form an image on the sheet; a fixing part which (i) secures a fixing nip by bringing outer circumferential surfaces of first and second rotating bodies into contact with each other, (ii) upon receiving a second instruction, heats the first and second rotating bodies until a temperature thereof reaches a target temperature, and (iii) thermally fixes the image onto the sheet passing through the fixing nip; and a determiner which determines output timings of the first and second instructions such that a timing at which a leading end, in a sheet convey direction, of the image formed on the sheet reaches the fixing nip and a timing at which the temperature of the first and second rotating bodies reaches the target temperature match each other.