A hydrocarbon production system (100) capable of efficiently producing hydrocarbon containing a high-calorie gas by securing hydrogen and carbon monoxide required for hydrocarbon synthesis using water and carbon dioxide as raw materials is obtained. The hydrocarbon production system includes an electrolytic reaction unit (10) that converts water and carbon dioxide into hydrogen and carbon monoxide through an electrolytic reaction, a catalytic reaction unit (30) that converts a product generated by the electrolytic reaction unit (10) into hydrocarbon through a catalytic reaction, and branch paths (41) and (51) that branch a portion of an outlet component of the catalytic reaction unit (30).