A non-invasive device for measuring blood temperature in a circuit for the
extracorporeal circulation of blood includes a line in which blood taken
from a patient flows. The device also includes a temperature sensor
connected to the line and provided with a device for measuring the
intensity of an electromagnetic radiation. The measuring device faces a
connecting portion or window of the line that is permeable by
electromagnetic radiation in a first wave band, and generates a first
signal, correlated with the electromagnetic radiation in the first band
and therefore with the temperature of the blood flowing in the line.