To strictly and efficiently separate an object to be separated by imparting classification function based on a particle size in a stage before separation action.

A feed-in means 12 feeding an object 11 to be separated comprising a metal having various particle sizes or a mixture of the metal and a nonmetal to a treatment position and separation means 19a-19b allowing constant force to act on the fed-in object to be separated to separate the object to be separated into the metal 17 and the nonmetal 18 or separating the metal by kind are provided. Classification means 16a-16c classifying the object 11 to be separated corresponding to a particle size to feed the same to the separation means 19a-19c are provided to the front stages of the separation means 19a-19c.