To separate liquid from fuel mixture before the liquid flows into an outlet fluid port.

A device 100 includes an annular body 32 having an open top portion, and a side face provided with fluid ports 37. Each of the fluid ports 37 has an inlet portion 37 in a tangent direction. A cap 34 covering the open top portion has an output fluid port 33. The cap 34 and the body 32 constitute a chamber. The inlet portions 37 in the tangent direction make the liquid-vapor mixture flowing into the inlet portions 37 swirl-rotate.