Abstract: The invention concerns a method for measuring the temperature of a preform in a facility comprising: a device for transporting preforms; a device for contact-less measurement of the temperature of a portion of the preform, comprising a sensor which is capable of measuring the temperature of the preforms in continuous travelling motion over a measurement section of the production path. The measurement device is equipped with an optical device which can project an image of the sensor in a measurement direction in the zone for measuring the temperature of the preforms, the measurement zone having a cross-section of dimensions less than the outer diameter of the portion of the preform to be measured. The invention also concerns a facility for implementing the method.