PURPOSE: To eliminate the need for a motor except the motors for rotating the respective rollers by rotating these rollers by the respective motors to hold up a pestle and separating the respective rollers by both cam wheels thereof and a rotary wheel and separating the pestle from the interval between the respective rollers.

CONSTITUTION: A pestle 1 is arranged between a pair of rollers 3L, 3R and one side of roller 3L is movably equipped. The roller 3L is elastically energized toward the other roller 3R by a spring 10. The pestle 1 is pinched between the rollers 3L, 3R and also the respective rollers 3L, 3R are rotated by the motors 12L, 12R to hold up the pestle 1 by the rollers 3L, 3R. A cam wheel 14 is provided to the roller 3L and a rotary wheel 15 is provided to the roller 3R. The cam wheel 14 and the rotary wheel 15 are mutually opposed. When the respective rollers are rotated to the position of a specified angle, the cam wheel 14 and the rotary wheel 15 are mutually engaged and the respective rollers 3L, 3R are pushed and separated while resisting the spring 10 and the pestle 1 is separated from the interval between the respective rollers and allowed to fall down.