Abstract: The present invention relates to a method for producing an ?-olefin low polymer through low polymerization reaction of an ?-olefin in the presence of a catalyst containing a transition metal-containing compound, an aluminum-containing compound and a hydrocarbon having 2 or more carbon atoms and substituted with a halogen atom, and a solvent, which comprises a reaction step, a purification step and a circulation step of circulating the unreacted raw material ?-olefin and the solvent from the purification step to the reaction step; and in which the amount of the olefin having 2 or more carbon atoms and substituted with a halogen atom that is supplied from the circulation step to the reaction step is within a range of from 0.1 to less than 200 (molar ratio) relative to the amount of the transition metal in the reaction step.