The present invention provides a cationic conductor comprising a block copolymer comprising: a polymer moiety having a structural unit represented by formula (1): wherein R represents an organic group obtained via polymerization of monomer compounds having polymerizable unsaturated linkages; Q represents an n+1-valence organic group bonded to R through a single bond; Z represents a functional group capable of forming an ionic bond to or having coordination ability to a cation; Mk+ represents a k-valence cation; and n and m are each independently an integer of 1 or larger, provided that Z forms an ionic or coordination bond to a cation; and a polymer moiety having addition polymerizable monomers.