Fuel Supply Device

A fuel supply device includes a fuel supply passage, a fuel pump, a pressure-regulating valve, and a housing. The fuel supply passage is in communication with the fuel injector. The fuel pump pumps the fuel to the fuel supply passage. The pressure-regulating valve regulates the pressure of the fuel in the fuel supply passage. The housing is disposed in the fuel tank. The housing accommodates the fuel pump and the pressure-regulating valve. The fuel supply passage is formed within the housing. The pressure-regulating valve is connected to an end portion of the fuel supply passage formed in the housing. The volume of the end portion of the fuel supply passage in the housing is configured to increase with increasing pressure of the fuel.