An electronic device comprises a body and a band being able to attach the body to a part of a human body. The body comprises first and second detectors and at least one processor. The first detector detects illuminance on an upper surface of the body. The second detector is located in a position distant from a position of the first detector in a short-side direction of the band and detects the illuminance on the upper surface of the body. The at least one processor executes predetermined processing if the at least one processor determines that at least one of first illuminance detected by the first detector and second illuminance detected by the second detector changes.