A device method and system are provided for measuring the body temperature in the area of the head. Reliable measured values are furnished even during movement and physical exercise. The device includes a head strap (1), whose strap elements (2, 3) are in contact at least partially as strap sections (7, 10) with the scalp of a user (4) of the headband and in which at least one of the strap sections (7) is designed for receiving a first temperature sensor (12) measuring the skin temperature.