A communication system and a receiving device ensure reducing a risk of performing pairing processing on an incorrect pair caused by presence of a large count of communication candidates, wherein the communication system includes an extractor to extract the communication candidates among a plurality of biological information measuring devices by the receiving device. The extractor compares radio field intensities of a plurality of pairing signals. A first threshold value specifies a lower limit of the radio field intensity at which a transmission of biological information is effectively achieved. The extractor extracts the at least one biological information measuring device transmitting the pairing signal at the radio field intensity exceeding a second threshold value as the communication candidate for this receiving device. According to an input operation by an operator, a selector selects the one biological information measuring device as a communication target among the communication candidates extracted by the extractor.
