A fuel supply device is obtained in which joint strength can be maintained in a joint portion of plural filter members configuring a fuel filter. A fuel filter with an overall bag shape is configured by welding together an upper face filter cloth a lower face filter cloth of the fuel filter at a welded portion. A sub tank upper side member and a sub tank lower side member nip the upper face filter cloth and the lower face filter cloth at a nipping position that is at a different position from the welded portion.

A bypass valve having an adjustable flow resistance for a device through which a fluid medium flows. The valve includes a seat and a body which is biased closed, and which is movable in the opening direction by a fluid medium pressure difference between the inflow and the outflow side of the valve when the pressure difference exceeds a threshold. A bypass flow path connects the inflow side to the outflow side through the seat. The bypass valve includes a screen disposed in the bypass flow path. The valve body has two different open positions that depend on the fluid medium pressure difference. The entire cross-section of the bypass flow path is covered by the screen in a first valve body open position with a lower pressure difference, and a screen-free bypass flow path cross-section is exposed in a second valve body open position with a greater pressure difference.