To solve the problem that the way of milling beans by a conventional manual coffee mill is tiring and requires to strike a body to drop the beans since the beans do not drop because the beans enter the level difference or gap of a hopper, and that this requires muscle power.

A hole of the same shape as a hole provided in the handle of the manual coffee mill to be mounted to a manual coffee mill body is provided at the center of a disk on the side face of which the ladder chain is fixed. A manual coffee mill mounting gear provided with a coffee bean entrance port is fixed to the manual coffee mill body between the hole and the side face instead of the handle. A chain wheel having a power adaptable to the ladder chain is engaged. The beans are ground by rotating the mill part of the manual coffee mill body by power. By providing protrusions on the lower face of the disk, the labor to strike the body to drop the beans can be saved by the protrusions scraping the beans entering the level difference or gap of the hopper. By this, the mechanism is provided which does not require to strike the body to drop the beans without muscle power and getting tired.