Disclosed is a method for producing 1-hexene that is capable of reducing the amount of by-product polymers when 1-hexene is produced through the trimerization reaction of ethylene. The method for producing 1-hexene comprises the following steps 1 and 2: step 1: the step of preparing a catalytic component by bringing a transition metal complex represented by any one of formulae (1-1) to (1-3) into contact with a specific organic aluminum compound in the absence of ethylene; and step 2: the step of trimerizing ethylene in the presence of a catalyst obtainable by bringing the catalytic component obtained in step 1 into contact with a specific boron compound.