A method for maintaining an ink jet head according to the invention includes at least one of a maintenance step of attaching a maintenance liquid to a nozzle surface of an ink jet head, which ejects a reaction solution including an aggregating agent for aggregating or thickening components of an ink composition, to clean the nozzle surface, and a maintenance step of covering and moisturizing the nozzle surface with a head moisturizing cap supplied with the maintenance liquid, in which the maintenance liquid includes a water-soluble organic solvent having a boiling point of 280° C. or less and water.