To provide a treatment method for efficiently separating selenium and tellurium from a mixture of selenium and tellurium.

The treatment method for recovering selenium contained in slime comprises introducing the mixture of selenium and tellurium into the step of melting and refining copper to alloy selenium and tellurium with copper, and electrolyzing it in the same method as electrolyzing copper to collect electrolytic copper; in another step, making selenium and tellurium accumulate in the copper electrolysis slime, leaching the copper electrolysis slime through oxidizing it with sulfuric acid to elute tellurium, and separating tellurium from selenium remaining in a residue after leaching; and preferably recovering copper telluride by adding metallic copper to the leached solution, and introducing the residue after leaching (copper-removed slime) into the step of recovering noble metals.