Disclosed is a dispersing agent to be used for dispersing metal particles, comprising a structural unit originating from a compound represented by a general formula of wherein R1 is a hydrogen atom or a methyl group, R2 is a hydrogen atom, an alkyl group with a carbon number equal to or greater than 1 and equal to or less than 9, a phenyl group, a bicyclopentenyl group, or a nonylphenyl group, x is 2 or 3, and n is equal to or greater than 1, and a structural unit that has an ionic group, wherein a number average molecular weight of the compound represented by general formula (I) is equal to or less than 10000.