Internal guiding of hydraulic hoses within telescopic boom arm presents difficult and time-consuming installation, significantly increases costs of manufacturing components and frequently requires demanding maintenance. By replacing the curent inner hose guiding and construction chain with double acting two-stage telescopic hydraulic cylinder, we would enable easier connection of the inner hydraulic hoses and eliminate the described problems. The master thesis contains an overview of existing solutions and patents, development and construction of hydraulic cylinder, theoretical calculations, analyses and measurements on the constructed prototype. Hydraulic cylinder works synchronously correctly. At lower oil flows it reaches the theoretical speed of working movement, but it does not reach the desired pulling force. The measured pulling force is 21,4 kN, which is approximately 7 kN less than the theoretically calculated force of reverse movement.