Abstract: A coffee bean grinder 1 has a hopper 2 into which coffee beans are inserted. The grinding unit 3 grinds coffee beans supplied from the hopper 2. The discharge unit 4 discharges coffee beans ground by the grinding unit 3. The mounting unit 5 mounts a portafilter 6 to be closely pressed against the bottom end of the discharge unit 4. The discharge unit 4 has a guide path 41 facing vertically downward, and a tapered section 42 in which the inner diameter increases towards the bottom. A sloped section 502 of a close-fitting member 50b, attached to the bottom end portion of the tapered section 42, is closely pressed against a top surface 63a of the filter basket 63 of the portafilter 6. The tapered section 42 has a hole 44 for allowing air in the airtight space to escape, thereby allowing the coffee beans to fall.