Disclosed is an IR measuring instrument (1) comprising a least one sensor element (29) which is sensitive to infrared radiation and generates an output signal (12) that depends on the radiation incident on the at least one sensor element (29). The output signal (12) for a predefined incident radiation can be varied by means of an integration time. The actual temperature prevailing on the at least one sensor element (29) is detected and is used for varying the integration time in such a way that the integration time compensates the influence of the temperature variations on the output signal (12) of the at least one sensor element (29).