An endoscope shaft made of a composite tube comprises an external tube and an internal tube which is softer and more resilient compared to the external tube as well as a helical spring for stiffening the composite tube. According to the invention, the helical spring in the relaxed state has an outer diameter which is larger than the inner diameter of the internal tube. Furthermore the helical spring is inserted in the internal tube preferably loosely at a spring bias, whereby it is radially pressed against the internal tube.
