To display the intensity of reception electric waves and to change a direction for easy communication by rotating a meter display section having an antenna.

When water flows, an impeller 4 is rotated, a permanent magnet at the upper portion of the impeller 4 is also rotated, and a rotary magnetic field is generated. A magnetic sensor 11 detects the rotary magnetic field, and a flow-rate integral value where a sensor signal is calculated is displayed at a liquid crystal display section 12. In the case of wireless meter reading, the intensity of received electric waves is displayed on five symbol marks 12a-12e. In response to the intensity of electric waves, the number of symbol marks to be lit is changed and displayed in a bar graph. By operating and rotating a transparent cover 17 with hands, an angle A is changed, and the best signal reception angle is selected.