To facilitate taking-out of floats by avoiding the situation of damage to equipment due to rubble and to easily and smoothly perform taking-out of sediments by sorting the sediments into large and small sizes.

A rubble sorting system includes a separating water tank Ta having a water tank body 1 into which the rubble G including the floats Gf floatable on water W and the sediments Gs sedimenting in the water W is thrown and in which the thrown-in floats Gf and the sediments Ga are separated due to specific gravity difference. The system provides a screen 10 which receives the sedimented sediments Gs on the side of a bottom part 4 of the water tank body 1, passes the sediments Gs of a prescribed size or less and filters off and removes them. The system discharges the water W and the sediments Gs passing through the screen 10 through a discharge pipe 13 to a storage tank Tb, and takes out the sediments Gs sedimenting in the storage tank Tb with a screw conveyor 40 so as to collect them.