TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The noble metal-containing particle comprises a noble metal-containing alloy containing a noble metal and a transition metal. The noble metal is an element comprising platinum, palladium, rhodium, osmium, ruthenium, and/or iridium. The transition metal is an element comprising vanadium, chromium, manganese, iron, cobalt, nickel, copper, and/or zinc. Preferred Composition: The noble metal-containing particle has a platinum content of 50-90, preferably 40-90 atomic %; iridium, rhodium, palladium, and/or ruthenium (5-30 atomic %); and cobalt, nickel, chromium, iron, and/or manganese (5-30 atomic %). The shell part has a platinum content of 80-100, preferably 40-90 atomic %. The core part has a platinum content of 40-90 atomic %. Preferred Condition: The core part has a platinum/Y (atomic ratio) of 6/1-2/3, where Y is cobalt. The shell part has a platinum/X (atomic ratio) of 6/1-2/3, where X is iridium. Preferred Method: The method further comprises separating the electroconductive carrier having deposited on it a noble metal-containing particle possessing a core-shell structure from the solution, washing the separated carrier, drying the washed carrier, firing the dried carrier in an atmosphere of an inert gas stream at 200-1100degreesC, and further retaining the fired carrier at 200-600degreesC.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The noble metal-containing particle comprises a noble metal-containing alloy containing a noble metal and a transition metal. The noble metal is an element comprising platinum, palladium, rhodium, osmium, ruthenium, and/or iridium. The transition metal is an element comprising vanadium, chromium, manganese, iron, cobalt, nickel, copper, and/or zinc. Preferred Composition: The noble metal-containing particle has a platinum content of 50-90, preferably 40-90 atomic %; iridium, rhodium, palladium, and/or ruthenium (5-30 atomic %); and cobalt, nickel, chromium, iron, and/or manganese (5-30 atomic %). The shell part has a platinum content of 80-100, preferably 40-90 atomic %. The core part has a platinum content of 40-90 atomic %. Preferred Condition: The core part has a platinum/Y (atomic ratio) of 6/1-2/3, where Y is cobalt. The shell part has a platinum/X (atomic ratio) of 6/1-2/3, where X is iridium. Preferred Method: The method further comprises separating the electroconductive carrier having deposited on it a noble metal-containing particle possessing a core-shell structure from the solution, washing the separated carrier, drying the washed carrier, firing the dried carrier in an atmosphere of an inert gas stream at 200-1100degreesC, and further retaining the fired carrier at 200-600degreesC. EXAMPLE - Ketjen Black EC (RTM: highly electroconductive carbon black) (4 g) having a Brunauer-Emmett-Teller surface area of 800 m2/g, an aqueous solution of cobalt nitrate hexahydrate (8.1 g), and an aqueous solution of dinitrodiammine platinum (platinum (Pt) concentration 1.0%) (400 g) were added together, stirred for one hour, mixed with ethanol (200 g) and sodium hydrogen boride (1 g), and stirred for one hour. The resultant mixture was heated to 85degreesC over a period of 30 minutes, further stirred and mixed at 85degreesC for six hours, and allowed to cool to room temperature over a period of one hour. The produced solution and an aqueous 5% tetramethyl ammonium hydroxide solution (10 g) were added and stirred together for one hour. The precipitate was separated by filtration and the resultant solid was dried under a reduced pressure at 85degreesC for 12 hours. The dried product was ground in a mortar to obtain a catalyst comprising Pt alloy particles having an average particle diameter of 4.0 nm. The concentration of Pt deposited was 50% based on the weight of the catalyst and the composition ratio of the Pt alloy particles (atomic ratio) was Pt0.75Co0.25. The catalyst was fired in an atmosphere of an inert gas stream at 600degreesC for one hour. The resultant catalyst powder was suspended for two hours in concentrated sulfuric acid (0.5M) (100 g) solution heated in advance to 50degreesC. The resultant precipitate was separated by filtration and the solid obtained was dried under a reduced pressure at 85degreesC for 12 hours. Catalyst particles resulting from liquation of cobalt from the surface of the catalyst particles were obtained.