To provide a highly accurate flow meter. A Flow meter comprising an inflow opening into which a measurement fluid flows, an outflow opening from which a measurement fluid flows, and a flow path connecting the inflow opening and the outflow opening, wherein the flow path is bent at a first bend portion, wherein: a first porous plate is disposed in the first bend portion of the flow path at an angle relative to the direction in which the flow path extends before and after the first bend portion, and a flow sensor for detecting the flow speed or flow volume of a measurement fluid that flows in the flow path, disposed on the inner wall of the flow path on the outflow opening side of the first bend portion.