An image forming apparatus includes: a recording material accommodating portion configured to accommodate a recording material; an image forming portion configured to form a toner image on the recording material fed from the recording material accommodating portion; a fixing portion configured to heat-fix the toner image formed on the recording material by the image forming portion; a storing portion configured to store information corresponding to the type of the recording material accommodated in the recording material accommodating portion; a detecting portion configured to detect that a predetermined operation is performed by an operator before the image forming apparatus receives an image formation instruction; and an executing portion configured to execute a start-up process, when the detecting portion detects the predetermined operation performed by the operator, over a time depending on the information stored in the storing portion.