A fixing apparatus includes: first and second rotatable member configured to heat-fix, at a nip therebetween, an unfixed toner image formed on a sheet by using a toner containing a parting agent; a casing, configured to accommodate the first and second rotatable member, including a sheet introducing opening and a sheet discharging opening; and a suppressing portion configured to suppress diffusion, toward the sheet discharging opening, of particles having a predetermined diameter resulting from a parting agent in the neighborhood of the sheet introducing opening, wherein the suppressing portion is provided in a position of 0.5 mm or more and 3.5 mm or less from a surface of the first rotatable member in a space in the casing from the sheet introducing opening to the sheet discharging opening.