The present invention is intended to provide a catalyst material that supports active species densely, thereby having higher catalytic performance and serviceability as, for example, an electrode for fuel cells. To achieve the above object, the present invention provides a process for preparing a catalyst material, including: an electrochemical polymerization step of electrochemically polymerizing a heteromonocyclic compound so that the surface of a conductive material is coated with polynuclear complex molecules derived from the heteromonocyclic compound; and a metallation step of coordinating a catalytic metal to the coating layer of the polynuclear complex molecules, characterized in that the potential applied in the electrochemical polymerization is 0.8 to 1.5 V.