To simply and surely sort by specific gravity only particulate material having almost constant particle size like lead buckshots.

This specific gravity sorting machine 8 sorts and takes out only lead bullets S3 from a liquid mixture with gravel 35 and lead bullets S3 mixed in rocking water W10, respectively having different specific gravities. The sorting machine is provided with intermediate particulate material 37 like alumina balls having a specific gravity intermediate between those of the gravel 35 and lead bullets S3 and placed on a passing mesh 31 in advance, and a rocking part 36 provided at the lower part of the mesh 31 and rocking the rocking water W10. An aperture diameter of the passing mesh 31 is set smaller than the particle size of the intermediate particulate material 37, and larger than the particle size of the lead bullets S3, to drop only lead bullets S3 through the passing mesh 31.