There is provided a bubble column type hydrocarbon synthesis reactor which synthesizes a hydrocarbon compound by a chemical reaction of a synthesis gas including hydrogen and carbon monoxide as main components, and a slurry having solid catalyst particles suspended in liquid. The hydrocarbon synthesis reactor includes a reactor main body which accommodates the slurry, a synthesis gas supplying section which supplies the synthesis gas to the slurry, and an introducing portion which introduces a cooling fluid having a lower temperature than the slurry into the reactor main body.