PURPOSE: To efficiently perform sanitary pulverization, agitation and grinding by rotating a cutter fitted to the rotation shaft of a closable drum-shaped mortar in one direction and in the reverse direction.

CONSTITUTION: A cutter 3 is fitted to the rotation shaft 2 rotated as a central axis in the center line of a closable drum-shaped mortar 1. The material being ground by the unidirectional rotation of the cutter 3 is mainly cut and pulverized and grinding of the material is mainly performed with the rear part of the cutter by rotating the cutter 3 in the direction reverse to the above-mentioned direction. The mortar 1 is tilted in a range within 40-50 degrees for the vertical and slantingly fixed. Furthermore, the upper side of the mortar 1 is formed into the cover 24 of an introduction port of a raw material and a discharge port having a cover 21 is provided to the bottom face of the lower side of the mortar 1. Further a scraping blade 34 on the lower side 20 in the mortar 1 is provided to the bearing part 35 of the rotation shaft 2 and a curved scraping blade 32 is provided to a motor shaft 31 projected to the inner part of the cover 24. As a result, sanitary pulverization, agitation and grinding can be efficiently performed.