This millstone comprises: a first millstone having a first grind area； a second millstone (350) which has a second grind area (351a) opposed to the first grind area and which is rotatable relative to the first millstone； and a heat dissipation mechanism which is provided on at least either the first millstone or the second millstone (350) and which dissipates friction heat generated by rotation of the second millstone (350) relative to the first millstone. The heat dissipation mechanism is provided at a location other than the first grind area and the second grind area (351a).
