NOVELTY - Powder of fine alloy particles comprises an uneven surface, which is a powder of an alloy composition. The powder has average grain size as measured under transmission electron microscopy (TEM) observation (D-TEM) of less than or equal to50 nm, and under TEM observation, and protruding points are observed on the surface of the particles and indentations are observed between the protruding points.    USE - The powder of fine alloy is used as a catalyst (claimed). It is used as a catalytic material in electrode catalysts useful for fuel cells and catalysts for use in automotive emissions control, or as a biomolecule marker or drug delivery system (DDS) or other material used in medical treatment.    ADVANTAGE - The power of alloy particles has fcc structure and T and M component to have a shape with drastic surface unevenness so that they can be provided with a surface shape that is suitable as a catalyst material. The unevenness of the surface of powder is drastic to increase its surface activity and to have even better catalytic activity.    DETAILED DESCRIPTION - Powder of fine alloy particles comprising an uneven surface, which is a powder of an alloy containing T and M in a composition ratio represented by formula of:    TxM1-x    The powder has average grain size as measured under TEM observation (D-TEM) of less than or equal to 50 nm, and under TEM observation, and protruding points are observed on the surface of the particles and indentations are observed between the protruding points.    T= greater than or equal to 2 of Fe, Co and Ni;    M = Pt, Pd and/or Ru;    x = 0.1-0.9    INDEPENDENT CLAIMS are also included for:    (1) method of producing the above powder of fine alloy particles having an uneven surface comprising dissolving metal salts containing the T and M components in a solution of polyhydric alcohol and/or its derivative with a boiling point of less than or equal to 100degreesC so that no solids remain, and placing that solution in an inert gas atmosphere at greater than or equal to 100-less than or equal to 250 degreesC to reduce the metal salts with the polyhydric alcohol and/or its derivative thus synthesizing a powder of alloy particles so that under TEM observation, the protruding points are observed on the surface of the particles and indentations are observed between the protruding points; and    (2) catalyst comprising the alloy particles supported on a carbon-based carrier substance.