PURPOSE: To reduce the milling sound of coffee beans while a cutter is rotated at a low speed, by providing such an arrangement that the outer arm part of the cutter is bent when a motor rotates at a low rotational speed in an initial milling stage, and the cutter is restored its original form when the motor rotates at a high speed.

CONSTITUTION: A cutter 10 is composed of a center bearing section 11 removably attached to a motor shaft, and a pair of cutter blades 12, 12. Each cutter blade 12 is divided at the position of a shaft 13 in the intermediate part thereof into a stationary blade 12a and a movable blade 12b which is formed thereon with a cutting edge 12c in the rotating direction, and a rising piece 12d at the front end thereof. Since a motor rotates at a low speed in an initial milling stage, the movable blades 12b of the cutter 10 are rotated about the shafts 13, and accordingly, the milling sound is reduced and the resistance by coffee beans is also reduced so that the cutter 10 is smoothly rotated. Further, after a predetermined time elapsing, when the motor rotates at a high speed, the movable blades 12b are returned to their original positions, and accordingly, normal coffee milling operation takes place.