A vital sign information processing system includes a sensor configured to be attached to a living body, and an information acquisition apparatus configured to acquire vital sign information of the living body through the sensor. A first memory is disposed in the sensor and stores first site information indicative of a site at which the sensor is to be used. A second memory is disposed in the information acquisition apparatus and stores second site information indicative of a site at which the information acquisition apparatus is to be used. A processor disposed in the information acquisition apparatus causes the information acquisition apparatus to perform notification when the first site information and the second site information are not matched.
