A VST (vapor separator tank) includes a casing including a lower case and an upper case joined to each other and having a fuel storage compartment formed therein to store liquid fuel, a pump arranged in the casing and pumping the liquid fuel stored in the fuel storage compartment, and a regulator (pressure regulator) sandwiched by the lower case and the upper case inside an accommodation space formed in the casing, and adjusting a discharge pressure of the pump to be constant. The casing includes a regulator support portion abutting on and supporting the regulator. Disclosed embodiments provide a vapor separator tank capable of holding a pressure regulator with a simpler structure and suppressing an increase in the number of parts, man-hours for assembly, and manufacturing costs.