To simplify the structure of a feeder to an antenna, improve the radiation of electric waves, widen directivity, and simplify watertight structure.

The rotation of an impeller 4 of a metering section 5 is detected by a magnetic sensor 10 in a meter indication section 8 in watertight structure, and is subjected to operation/integration by the electronic circuit of an electronic circuit board 14, and the amount of water usage is displayed on a liquid crystal display section 11. The amount of water usage is transmitted from the antenna 12 that is printed on glass for composing the liquid crystal display section 11 through window glass 16 by electric waves. The upper opening of the case 9 is made watertight by an O ring 15 and the window glass 16. A meter indication section 8 is fitted to a lower case 1 by an upper case 21 via a packing 20.