To produce 1,2-dichloroethane while preventing the corrosion of a dichloroethane-recovery column and a low-boiling component distillation column by applying a specific treatment in the reaction of ethylene with chlorine in liquid phase in the presence of a catalyst using a specific method.

The objective 1,2-dichloroethane (EDC) is produced by reacting ethylene with chlorine in liquid phase in the presence of a catalyst, separating high-boiling component from the produced EDC in gaseous phase using a high- boiling component distillation column and a vacuum distillation column and then separating low-boiling component and gaseous component with an EDC- recovery column or a low-boiling component distillation column to obtain purified EDC. In the above process, the EDC discharged from the high-boiling component distillation column is purified by neutralizing the vapor (condensed liquid) discharged from the EDC-recovery column or the low-boiling component distillation column with a basic substance (e.g. caustic soda) to remove hydrogen chloride and purify the product by separating the low-boiling component and the gaseous component by the EDC-recovery column or the low-boiling component distillation column.