A belt-nip system fixing apparatus reduces the frequency of replacing a pressure belt or a sliding sheet. In accordance with a sheet measurement in a roller axis direction, the fixing apparatus switches a pressure distribution in the roller axis direction between a low-pressure load distribution in which pressure is greatest at a center pressure switching projection of a hard pad, and pressure gradually lessens towards pressure switching projections near the ends of the hard pad, and the pressure in a range of 216 [mm] in a center in the roller axis direction is greater than or equal to a necessary pressure for fixing (a predetermined value Nm) while the pressure in other projections near the ends is below the predetermined value Nm, and a high-pressure load distribution in which the pressure throughout the total area in the roller axis direction equals or exceeds the predetermined value Nm.