The present invention extracts precious metals from an acidic solution containing precious metals in an early and highly efficient manner. Provided is an extraction agent for precious metals that is represented by the general formula below. In the formula, R1 and R2 each represent the same alkyl group or different alkyl groups, R3 represents a hydrogen atom or an alkyl group, and R4 represents a hydrogen atom or a discretionary group that is not an amino group and that bonds to α carbon as an amino acid. By subjecting an acidic solution containing precious metals to solvent extraction using the extraction agent for precious metals, a plurality of precious metals can be recovered all at once from a solution containing a large amount of various impurities.