A measuring device (10) that is portable is configured to be capable of BLE communication with an information processing device (20). The measuring device (10) is configured to acquire living body related information of a user, receive a first advertising packet transmitted at a predetermined cycle from an information processing device (20), start encryption of the living body related information using a public key when the first advertising packet is received, calculate an estimated distance between the measuring device (10) and the information processing device (20) on the basis of a received signal strength indicator of the first advertising packet, and transmit a second advertising packet including the living body related information thus encrypted when the estimated distance is less than a first threshold.