Assist tool and sensor kit

A sensor kit comprising:

• a sensor tool including a physiological information detector for obtaining physiological information on a subject;
• and
• an assist tool configured to be attached to a finger of the subject to accommodate the physiological information detector and configured to assist in obtaining the physiological information on the subject by the sensor tool,
• wherein the assist tool includes:
• a support body configured to be placed on a first side of the finger in a case where the support body is attached to the finger;
• a bag body configured to be placed on a second side, the second side being opposite to the first side of the finger with respect to the finger;
• and
• a fluid passage communicating with inside of the bag body,
• the first side is one of a pad side of the finger and a nail side of the finger,
• the second side is an other one of the pad side of the finger and the nail side of the finger,
• the physiological information detector is configured to be placed between the finger and the support body, and between the finger and the bag body, and
• the support body is provided with a spacer such that the finger does not enter a fingertip side of the bag body.