Inorganic fibers including the following composition, SiO2, Al2O3, MgO and CaO being main components, and the inorganic fibers being produced by a melting method: SiO2: 3.0 wt % or more and less than 48.0 wt %, Al2O3: more than 20.0 wt % and 80.0 wt % or less, MgO: 1.0 wt % or more and 50.0 wt % or less, CaO: 1.0 wt % or more and 50.0 wt % or less, and Fe2O3: 0.0 wt % or more and less than 1.0 wt %.