A composite particle for an electrode including an active material particle, carbon nanofibers bonded to the surface of the active material particle, and a catalyst element for promoting the growth of the carbon nanofibers, wherein the active material particle includes an electrochemically active phase. As the catalyst element, for example, Au, Ag, Pt, Ru, Ir, Cu, Fe, Co, Ni, Mo, Mn and the like are used. The composite particle for an electrode may be produced, for example, by means of a method which includes: a step of preparing an active material particle including a catalyst element for promoting the growth of carbon nanofibers at least in the surface layer of the active material particle; and a step of growing carbon nanofibers on the surface of the active material particle in an atmosphere including a raw material gas.