The present invention provides a rare metal/platinum-group metal extractant, which has a completely new structure compared with the conventional rare metal/platinum-group metal extractant and which exhibits excellent extraction performance; it also provides a method for extracting rare metals and platinum-group metals using the extractant. The rare metal/platinum-group metal extractants of the present invention is the one to extract rare metals and platinum-group metals by contacting a solution, in which several kinds of rare metals and platinum-group metals are dissolved, with a solution in which a cyclic phenol sulfide of the following Formula (1) is dissolved to make the rare metals and platinum-group metals move into the cyclic phenol sulfide solution.