NOVELTY - Electrode catalyst (20) (I), comprises: a complex support (10) comprising at least one metal oxide (13) and a carbon-based material (11); and a palladium (Pd)-based catalyst (21) supported by the complex support.    USE - (I) is useful for a fuel cell (claimed), preferably phosphoric acid fuel cells, polymer electrolyte membrane fuel cells, and direct-methanol fuel cells.    ADVANTAGE - (I): is a non-platinum (Pt) based electrode catalyst with excellent oxygen reduction capability; includes the Pd-based metal catalyst, which does not contain any Pt; and has improved reduction current density compared to a general Pd/carbon electrode catalyst. The Pd-based metal catalyst has improved catalytic characteristics due to an interaction (bonding) between the Pd-based metal catalyst and the metal oxides, and higher stability and greater catalytic characteristics as it is supported by the complex support including the metal oxides, compared to a Pd-based metal catalyst only supported by a carbon support.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a method of manufacturing an electrode catalyst (20) for a fuel cell, comprising: dissolving a precursor of a Pd-based catalyst (21) in a solvent and preparing a mixture solution for a catalyst; adding a complex support (10) comprising at least one metal oxide (13) and a carbon-based material (11) to the mixture solution for a catalyst and stirring the mixture solution to which the complex support is added; drying the mixture solution for a catalyst, to which the complex support is added, to disperse the precursor of the Pd-based catalyst on the complex support; and reducing the precursor of the Pd-based catalyst dispersed on the complex support; and    (2) a fuel cell comprising: an electrode comprising (I); and an electrolyte membrane.    DESCRIPTION OF DRAWING(S) - The figure is a diagram of an electrode catalyst for a fuel cell in which a Pd-based catalyst is supported by the complex support.    Complex support (10)    Carbon-based material (11)    Metal oxide (13)    Electrode catalyst (20)    Pd-based metal catalyst (21)