To provide an apparatus for composting garbage in which water vapor is easily transpired, excellent deodorization effect is exhibited and an operation is continuously carried out without taking out the whole composted material.

An upper cover 4 in which a ventilation member holding a deodorant is mounted is provided to the upper part opening part 2 of a horizontally placed drum 1, a rotary shaft 3 with a handle 9 is provided to the center part of the drum 1 and stirring blades are arranged on the tip part of a stirring blade supporting arm installed on the rotary shaft 3 so that an angle formed with the rotary shaft is changed to be reduced one after another.