To provide a wireless field apparatus capable of dispensing with a secondary battery with the finite number of charging times.

The wireless field apparatus is incorporated with a measuring module for measuring a physical quantity of measuring object fluid flowing inside a pipe and a wireless module for performing a wireless communication to the outside. The wireless field apparatus includes: an energy storage/supply device being used as a power supply for actuating the measuring module and the wireless module using that positive/negative charges are stored in an interface between a solid and a liquid; physical quantity/electric energy converting means for converting the physical quantity of the measuring object fluid into the electric energy and outputting the electric energy; a power storage part for charging the energy storage/supply device by the electric energy output from the physical quantity/electric energy converting means.