PURPOSE: To prevent being charged the same charge as the case of receiving data without an error even at the time of receiving erroneous data by providing an error generation detecting means and changing a charging rate according to an error generating rate in a prescribed time.

CONSTITUTION: An error correcting circuit 1 corrects the error of data to be received, a code to indicate whether or not the error is corrected is added to the received data, and the data are outputted. An error detecting and error frequency counter 3 outputs the generating state of the error from an error correction result. A charge discriminating circuit 7 fluctuates the charging rate according to the error generating frequency from such an output result. Thus, when a receiving person receives the erred data, the charge is discounted, and a disadvantage can be canceled.