The paper presents to theoretical and experimental investigation of the plasma source on the basis of the electrodeless microwave discharge in a mode of electron cyclotron resonance. Steady interest in the sources of plasma of this type is defined as insufficiently complete study of physical phenomena accompanying the microwave discharge, and the perspective of its application in ion accelerators, and also for creation of a nonequilibrium plasma in plasma chemical reactors. Source plasma excited by microwave discharge in a cylindrical resonator with dielectric walls, placed in a non-uniform axial-symmetrical magnetic field of a permanent ring magnet. To create electromagnetic oscillations such E01 in cylindrical resonators used broadband enter the microwave energy, which is a conical transformer attached to the dielectric window in the end. Frequency range, the amplitude of the electromagnetic waves and spatial change of magnitude of a magnetic field induction had been chosen the way that the conditions of electron cyclotron resonance can be created in a quite large volume of cylindrical resonator. Modeling matching transformer made using MICROWAVE STUDIO software v 5.0.0. Experimental study of microwave discharge carried out in the range of 3.2 - 3.9 GHz. The investigated area of the glow discharge, as well as the dependences of the standing wave ratio (VSWR) frequency and power generator are in good qualitative agreement with the results of mathematical modeling of electromagnetic fields in the resonator region of the plasma generator. The study has found that the complex structure of the discharge at low gas pressure is determined by the configuration of a strongly inhomogeneous magnetic field. Thus the ignition and burning of the discharge can occur only due to the oscillating electrons, which do not leave the discharge and can ionize the neutral gas molecules.