Applications of up-to-date cryoelectronics, especially in quantum microwave engineering, require instruments that operating identically to an optical beam splitter. Using niobium technology for the application of thin film structures, we have fabricated a microwave signal power splitter with central frequency f0 = 7.2 GHz. We have demonstrated experimentally that, in the 1GHz band around central frequency f0, the characteristics of the second and the third output ports are in the range of –3 ± 0.8 dB of the signal input power. The attenuation within power transfer from signal ports to the insulation port is 10 dB. The above mentioned characteristics have been obtained at an operating temperature below the superconducting transition temperature.