A detecting system includes a sensor and a receiving device. The sensor is introduced into a living body through a mouth of the living body, transmits time-point related information associated with a plurality of time points different from one another, detects a physical amount in the living body, and transmits detection information representing the detected physical amount at each of the plurality of time points. The receiving device receives the time-point related information transmitted by the sensor and is on standby for receiving the detection information transmitted by the sensor on the basis of the plurality of time points associated with the received time-point related information.
