To provide an electric power measuring system easy to mount even in a narrow place with a reduced volume occupied by the measuring system reduced, by dispensing with a line dedicated to transmission for communication between detectors for detecting the quantities of electricity used in respective loads, and a center device for compiling data on the quantities of electricity detected in the detectors and used in the loads.

The detectors 103, 104, 105, and 106 are provided for the respective loads which are electric appliances used in customers, and data on electric current used in the respective loads are prepared by the detectors and transmitted to the center device 102 by radio wave or distribution line carriage. Meanwhile, the center device 102 is for detecting the voltage of a distribution line, operating data transmitted from the detectors 103, 104, 105, and 106 and related to the electric current used in the respective loads, and calculating used electric power related to the respective loads, which are stored therein and reported.