PURPOSE: To obtain the load survey system in which measured data are sent efficiently and accurately.

CONSTITUTION: When measured data are sent to a transmitter, the data are sent from a carrier section 36 as a telegraphic message including its own ID number and measurement data measured by a power measurement section 31. When the transmitter cannot receive the telegraphic message accurately due to an effect such as external disturbance, a control section 33 decreases the length of the telegraphic message upon the receipt of a re-transmission request from the transmitter to send the processed telegraphic message to the transmitter again from the carrier section 36.