Measuring device , which is designed to be detachably fixed to a hot air blower assigned to the measuring device , the measuring device comprising a housing and measuring means for contactless measurement of a surface temperature of an object that can be heated with the hot air blower along a measuring axis , wherein the measuring device is designed with fixing means in such a way that, when it is arranged on the hot air blower , the measuring device is aligned for detecting the surface temperature in a region in front of a hot air outlet of the hot air blower , the measuring device comprises a common target device for the measuring device and the hot air blower for simultaneous determination of an optimal measuring distance (M) between the measuring device and the object and an optimal working distance (A) between the hot air blower and the object to be heated, which working distance is specified by the manufacturer of the hot air blower, with the optimal measuring distance (M) being the distance for which the measuring device is designed and at which the measuring result has the greatest accuracy, the target device comprises light beam generating means for generating at least two light beams running at an angle to one another, which, when the measuring device is arranged on the hot air blower , converge at a meeting point (T) in a region in front of the hot air blower , with the meeting point (T) located in a main outlet flow of the hot air blower representing the optimum measuring and working distance (A, M) to the object , and the measuring device is designed as a device that can be attached to the hot air blower, and wherein the fixing means are designed to be so rigid that they tilt the measuring device , in a state arranged on the hot air blower , relative to the main outlet flow by a fixed tilting angle such that the measuring axis intersects the main outlet flow at the meeting point (T). a housing and measuring means for contactless measurement of a surface temperature of an object that can be heated with the hot air blower along a measuring axis , wherein the measuring device is designed with fixing means in such a way that, when it is arranged on the hot air blower , the measuring device is aligned for detecting the surface temperature in a region in front of a hot air outlet of the hot air blower , the measuring device comprises a common target device for the measuring device and the hot air blower for simultaneous determination of an optimal measuring distance (M) between the measuring device and the object and an optimal working distance (A) between the hot air blower and the object to be heated, which working distance is specified by the manufacturer of the hot air blower, with the optimal measuring distance (M) being the distance for which the measuring device is designed and at which the measuring result has the greatest accuracy, the target device comprises light beam generating means for generating at least two light beams running at an angle to one another, which, when the measuring device is arranged on the hot air blower , converge at a meeting point (T) in a region in front of the hot air blower , with the meeting point (T) located in a main outlet flow of the hot air blower representing the optimum measuring and working distance (A, M) to the object , and the measuring device is designed as a device that can be attached to the hot air blower, and wherein the fixing means are designed to be so rigid that they tilt the measuring device , in a state arranged on the hot air blower , relative to the main outlet flow by a fixed tilting angle such that the measuring axis intersects the main outlet flow at the meeting point (T). <EOS>