To make frictional heat of upper and lower millstones radiate well to make easy the cleaning of pulverized material which has fallen to the outside in the way which finely pulverizes tea young leaves or the like by the upper and lower millstones.

Plural supports 4 are erected on the upper surface of a lower case 6 so that spaces are formed therebetween. The supports 4 are provided with a preliminary pulverizing part 2 and a main pulverizing part 3. The side peripheral surface of the main pulverizing part 3 is exposed to the above spaces to increase the radiation of heat of the main pulverized part 3. A cooling fan 33 is preferably installed for blowing air to the side peripheral surface of the main pulverizing part 3.