A portable manual grinder has a driving section, a grinding section and a discharging section coaxially connected from top to bottom. The driving section has a drive shaft that drives a central axis of the grinding section. The drive shaft is connected to a gear set that increases the gear ratio to facilitate manual grinding. The grinding section comprises an upper grinding section and a lower grinding section that are coaxially disposed and mated together. The upper and lower grinding portions include corresponding blades extending therefrom. The bottom section of the lower grinding section has one or more holes in communication with the discharge section. The driving section and the upper grinding section are magnetically attracted and connected to each other and the upper grinding section and the lower grinding section are magnetically attracted and connected to each other.