A catalyst containing a carbon support and a core-shell nanoparticle supported on the carbon support, wherein a core of the core-shell nanoparticle is cobalt metal not containing a heterogeneous element and the shell contains carbon. The catalyst for an oxygen reduction reaction of the present disclosure is a catalyst in which the cobalt core-carbon shell nanoparticle is supported on the carbon support through ligand stabilization and heat treatment. The catalyst can be synthesized to have high dispersibility. In particular, it can be used as an electrode catalyst of a cathode to improve the oxygen reduction activity and durability of a fuel cell operating under an alkaline atmosphere.