A mill includes a first mill having a first grinding region, a second mill having a second grinding region opposed to the first grinding region and provided to be rotatable relatively to the first mill, and a heat radiation mechanism which is provided in at least one of the first mill and the second mill and radiates friction heat generated as a result of rotation of the first mill and the second mill relative to each other, and the heat radiation mechanism is provided in a portion except for the first grinding region and the second grinding region.