A fuel supply system includes a fuel pump, a filter element, a pressure regulating valve, and a filter case. The filter case is configured to cover radially inner and outer surfaces of the filter element. The filter case has a receiving portion. A bottom portion of the receiving portion and an end portion of the filter element defines therebetween an outflow chamber for storing fuel. The outflow chamber includes a partitioning member that partitions the outflow chamber into first and second outflow chamber sections. The second outflow chamber section is communicated with an inlet portion of the pressure regulating valve. The partitioning member has a communication portion that provides communication between the first and second outflow chamber sections.