An endoscope, especially a mediastinoscope, includes an elongated shaft and a head piece situated at a proximal end section of the shaft, wherein a heat source is arranged in the head piece. At least one heat pipe extends inside the shaft, wherein a proximal end section of the at least one heat pipe is thermally coupled to the heat source and the endoscope includes an optical system which is closed by a cover glass arranged in a distal end section of the shaft. The heat source is a light source for generating an illumination radiation. The at least one heat pipe extends in the distal direction as far as the distal end section of the shaft, and at least one distal end section of the heat pipe is thermally coupled to the distal end section of the shaft.