CATALYST, AND ELECTRODE CATALYST LAYER, FILM ELECTRODE ASSEMBLY, AND FUEL CELL EACH INCLUDING SAID CATALYST

The present invention has an obj ect to provide a catalyst having excellent oxygen reduction reaction activity. The present invention relates to a catalyst comprising a catalyst support and a catalyst metal supported on the catalyst support, wherein a specific surface area of the catalyst per support weight is 715 m/g support or more or a covering ratio of the catalyst metal with an electrolyte is less than 0.5, and an amount of an acidic group of the catalyst per support weight is 0.75 mmol/g support or less.