Abstract: A method is provided for the contactless determination of the body core temperature of a person (7), wherein the surface temperature of the person (7) is detected at a measuring site (6) on the body by means of a temperature sensor unit (2) arranged at a spaced location therefrom. The sensor signal generated by the temperature sensor unit (2) is sent to an evaluating unit (3) for evaluating the sensor signal and for calculating the body core temperature, and the temperature signal generated in the evaluating unit (3) is sent to a display unit (4) for the optical display of the body core temperature determined. The temperature sensor unit (2) locally identifies a measuring area (8) on the body in a first step and the measuring area (8) on the body is resolved by the temperature sensor unit (2) in a second step such that the measuring site (6) on the body is detected and the detection is carried out by the temperature sensor unit (2) at this measuring site (6) on the body.