The present invention has as its object the provision of a solid polymer fuel cell catalyst exhibiting high durability and high power generation performance regardless of the humidification conditions or load conditions.The present invention relates to a solid polymer type fuel cell catalyst which is comprised of a carbon material which carries a catalyst ingredient, wherein the amount of adsorption of water vapor (V10) at 25° C. and a relative humidity of 10% of the carbon material is 2 ml/g or less and the amount of adsorption of water vapor (V90) at 25° C. and a relative humidity of 90% of the carbon material is 400 ml/g or more.