Abstract: An apparatus for separating particles in accordance with the sphericity of the particles is disclosed. The apparatus includes a housing which is supplied with air having a desired humidity, and which accommodates therein a cylindrical rotor with a horizontal shaft. The particles are charged into the housing from a hopper above the rotor, and tend to adhere onto the peripheral surface of the rotor with adhesive force which is dependent on the sphericity of each particle. The rotor is placed into a slow rotation and subjected to vibration whereby non-spherical particles and spherical particles are collected in respective receptacles arranged on both sides of the rotor shaft.