There is provided a hydrocarbon distillation separation apparatus for fractionally distilling hydrocarbon compounds discharged from a Fisher-Tropsch synthesis reactor synthesizing hydrocarbon compounds, comprising a heavy hydrocarbon fractionator configured to fractionally distil liquid heavy components of the hydrocarbon compounds discharged from the reactor into a first middle distillate and a wax fraction, a light hydrocarbon fractionator configured to fractionally distil gaseous light components of the hydrocarbon compounds discharged from the reactor into a second middle distillate and a light gas fraction, a light hydrocarbon separator configured to separate hydrocarbon compounds equivalent to naphtha from the light gas fraction; and a mixing section configured to mix the first and second middle distillates, and the hydrocarbon compounds equivalent to naphtha separated from the light gas fraction by the light hydrocarbon separator.