To provide an apparatus for producing a fuel from wood waste that surely prevents a pulverized mixture from being discharged in a state that wood waste having a particle size larger than a prescribed size is mixed into the pulverized mixture and can produce a fuel from wood waste at a low cost with a simple construction, to provide a method for treating wood waste and to provide a cement calcination installation.

A first classifier 21 is formed at the upper part of a chute 18 (a reflux passage). A second classifier 22 is formed at an inlet opening 17a of a discharging tube 17 (an inner cylinder) in the form of a substantially cylindrical shape extending outwardly of the discharging tube 17, i.e., toward the direction of a pulverizing table 14. The second classifier 22 is constructed of a net sieve of a substantially cylindrical shape having a bore diameter equal to that of the discharging tube 17.