A fuel supply device includes: a cover attached to an upper wall of a fuel tank; a pump unit disposed on a bottom wall of the fuel tank; and a connecting strut that connects the cover and the pump unit with each other. The pump unit includes: a unit body supported by the connecting strut in a radial direction and a thrust direction, and a fuel pump arranged on the unit body to pump fuel drawn from the fuel tank toward an internal-combustion engine. The fuel pump is located offset toward the connecting strut from a width center of a width from a thrust support part where the unit body is supported by the connecting strut to an end part of the unit body opposite from the connecting strut in a specific transverse direction.