In order to extend the measuring range of the float-area-type flow meter, a float with a hole was tested. The flow entering the tapered tube of the conventional float-area-type flow meter is passsed, in this case, both the clearance between the tapered tube and the float and the hole of the float, and the total flow rate is indicated by the position of the float. The flow rate characteristics of this type of flow meter was theoretically and experimentally investigated.The curve for the resulting flow rate characteristics was found to shift almost parallel to itself with an increase in the diameter of the hole. Typical basic data for designing this type of flow meter were presented.