A sensor pad kit includes a sensor pad (701) which is flexible, and one surface of which is adhesive, having a sensor holding portion (702a) to which a sensor device (550) is to be attached, and at least two extended portions (718) extending toward an outer side from the sensor holding portion (702a) in a plan view, a fixing member (775) which fixes the sensor device to the sensor holding portion, and a peelable film (771) which is stuck to an adhesive surface of the sensor pad.
