PURPOSE: A grain crusher is provided to minimize working time and manpower due to cleaning and replacing work, and to easily assemble and dissemble a consumable sorting net which is assembled to a crushing sorting drum. CONSTITUTION: A grain crusher includes the following: a grinding part(3) crushing grains which are put into an upper input hopper(2); a discharge part(4) discharging grain powder which is crushed in the grinding part; a pulverizing part discharging the clean air and collecting the powder included in the air; and a cyclone(5) connected to the discharge part. A branch supply pipe(9) is formed on an inlet pipe. An injection screw(8) is installed on an input pipe(6).
