A liquid developer which has excellent preservability, storage stability for a long period of time, and fixing characteristics of toner particles and which is also harmless to the environment is provided. The liquid developer contains an insulation liquid and toner particles dispersed in the insulation liquid. The insulation liquid contains a saturated fatty acid and at least one of an eicosapentaenoic acid component and a docosahexaenoic acid component. The liquid developer may contain an antioxidizing agent and an oxidation polymerization accelerator for accelerating an oxidation polymerization reaction of the eicosapentaenoic acid component or the docosahexaenoic acid component during a fixing process. Further, an image forming apparatus for use with the liquid developer is also provided.