ELECTRODE CATALYST FOR FUEL CELL, PRODUCTION METHOD THEREOF, FUEL CELL ELECTRODE CATALYST LAYER CONTAINING SAID CATALYST, FUEL CELL MEMBRANE-ELECTRODE ASSEMBLY USING SAID CATALYST OR CATALYST LAYER, AND FUEL CELL

Provided is a catalyst for fuel cell which has a high catalytic activity and enables maintaining the high catalytic activity. Disclosed is an electrode catalyst for fuel cell comprising a catalyst carrier containing carbon as a main component and a catalytic metal supported on the catalyst carrier, wherein the catalyst has the R' (D'/G intensity ratio) of 0.6 or less, which is the ratio of D' band peak intensity (D' intensity) measured in the vicinity of 1620 cm -1 relative to G band peak intensity (G intensity) measured in the vicinity of 1580 cm -1 by Raman spectroscopy, and the volume ratio of a water vapor adsorption amount relative to a nitrogen adsorption amount at a relative pressure of 0.5 in adsorption isotherm is 0.15 or more and 0.30 or less.