NOVELTY - A fuel cell catalyst comprises an electronically conductive support and catalyst fine particles supported on the support, where the catalyst is alloy comprising platinum, ruthenium, germanium and metal e.g. aluminum (Al).    USE - For membrane electrode assembly, which is used in fuel cell (claimed).    ADVANTAGE - The fuel cell catalyst has high activity than the platinum-ruthenium (PtRu) alloy; and has excellent stability. The present catalyst prevents carbon monoxide (CO) from poisoning more effectively than the conventional PtRu catalyst.    DETAILED DESCRIPTION - A fuel cell catalyst comprises an electronically conductive support and catalyst fine particles supported on the support, where the catalyst is alloy comprising platinum, ruthenium, germanium and metal of formula PtuRuxGeyT'z (I).    T'=aluminum (Al), silicon (Si), nickel (Ni), tungsten (W), molybdenum (Mo), vanadium (V), tantalum (Ta), titanium (Ti), hafnium (Hf), tin (Sn), zirconium (Zr), niobium (Nb) and chromium (Cr);    u=30-60 atmosphere (atm) %;    x=20-50 atm %;    y=0.5-20 atm %;    z=0.5 to 40 atm %.    where T'-element in the largest amount is Al, Si, Ni, W, Mo, V or Cr, the content of the T'-elements atoms connected with oxygen bonds is not more than four times as large as that of the T'-elements atoms connected with metal bonds on the basis of X-ray photoelectron spectrum analysis; and where T'-element in the largest amount is Ti, Hf, Sn, Ta, Zr or Nb, the content of the T'-elements atoms connected with metal bonds is not more than twice as large as that of the T'-elements atoms connected with oxygen bonds on the basis of X-ray photoelectron spectrum analysis. INDEPENDENT CLAIMS are included for following:    (1) preparation of the fuel cell catalyst involving attaching platinum (pt), ruthenium (Ru), germanium (Ge) and the T'-element onto electronically conductive support by sputtering or by vapor-deposition; and    (2) a membrane electrode assembly comprising a cathode, an anode containing the fuel cell catalyst, and a proton-conductive membrane placed between cathode and anode.