The electron energy distribution function in a microwave discharge at the electron cyclotron resonance (ECR) condition is studied using a two-dimensional Fokker–Planck equation in the bounce-averaged approach. Our model takes into account the effects of linearized Coulomb collisions, electron cyclotron resonance heating in the quasilinear approximation, the effects of ionization and excitation of atoms, elastic scattering of electrons on atoms, and the self-consistent ambipolar potential. The plasma is considered to be slightly collisional, so that bounce averaging is valid. We perform a numerical investigation of the Fokker–Planck equation and obtain the dependences of the discharge characteristics on the parameters of the model, such as breakdown threshold values of neutral density, and the dependence of the electron density, temperature and ambipolar potential on the parameters of the ECR wave and gas density. Some results are compared with experimental data.