Master thesis topic “Measuring ionizing radiation from the Sun on Earth's surfaces” consist of two parts. In the first, theoretical, part of the work is a brief explanation of radiation, its kind and its properties. Various sources of radiation are described and the Sun is described as an important source of radiation. A short description of the Earth's atmosphere by layers and its influence on Sun's radiation is briefly described. The principle of the Geiger - Müller counter used to detect α, β and γ-particles is described. In the second experimental part of the work, measurements are required to determine the proportion of ionizing radiation coming to Earth's surface from the Sun. Finally, a detailed analysis of the obtained data was made.