A liquid developer includes: a carrier liquid; and toner particles that are dispersed in the carrier liquid and that includes a styrene-based thermoplastic elastomer, a styrene-based thermoplastic resin, and a quaternary ammonium base-containing polymer having a constituent unit expressed by Chemical Formula I: wherein R1 represents hydrogen or an alkyl group with a carbon number equal to or less than 3, R2 represents an alkylene group with a carbon number equal to or less than 18, R3 to R5 represent an alkyl group or an aralkyl group with a carbon number equal to or less than 18, X represents —COO— or —CONH—, and Y− represents a halogen ion or an anion having a —COO— group or a —SO3— group in the structure thereof.